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{{Infobox mineral
| name = Chalcedony
| category = [[Oxide minerals]], [[quartz]] group
| image = Quartz-83325.jpg
| imagesize = 260px
| caption =
| formula = [[Silica]] (silicon dioxide, {{Chem|Si|O|2}})
| molweight = 60 g/mol
| color = Various
| habit =
| system = Trigonal or monoclinic
| twinning =
| cleavage = Absent
| fracture = Uneven, splintery, conchoidal
| mohs = 6 - 7
| luster = Waxy, vitreous, dull, greasy, silky
| refractive =
| opticalprop =
| birefringence =
| pleochroism =
| streak = White
| gravity = 2.59 - 2.61
| density =
| melt =
| fusibility =
| diagnostic =
| solubility =
| diaphaneity = Translucent
| other =
| references = <ref>{{Cite book |title=Minerals of the World |last=Duda |first=Rudolf |last2=Rejl |first2=Lubos |date=1990 |publisher=Arch Cape Press}}</ref>
}}
'''Chalcedony''' ({{IPAc-en|pron|k|æ|l|ˈ|s|ɛ|d|ə|n|i}}) is a [[cryptocrystalline]] form of [[silica]], composed of very fine intergrowths of [[quartz]] and [[moganite]].<ref name="heany_1994">{{Cite book |title=Silica: Physical Behavior, geochemistry and materials applications |last=Heaney |first=Peter J. |date=1994 |editor-last=Heaney |editor-first=P. J. |series=Reviews in Mineralogy |volume=29 |pages=1–40 |chapter=Structure and Chemistry of the low-pressure silica polymorphs |editor-last2=Prewitt |editor-first2=C. T. |editor-last3=Gibbs |editor-first3=G. V.}}</ref> These are both silica [[mineral]]s, but they differ in that quartz has a [[trigonal]] crystal structure, while moganite is [[monoclinic]]. Chalcedony's standard [[chemical structure]] (based on the chemical structure of quartz) is SiO<sub>2</sub> (silicon dioxide).
Chalcedony has a waxy luster, and may be semitransparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black. The color of chalcedony sold commercially is often enhanced by dyeing or heating.<ref name="gemsociety" />
The name ''chalcedony'' comes from the [[Latin]] ''chalcedonius'' (alternatively spelled ''calchedonius''). The name appears in [[Pliny the Elder]]'s ''[[Naturalis Historia]]'' as a term for a translucid kind of [[Jaspis]].<ref>{{Cite book |chapterurl={{google books|id=oHlGAAAAYAAJ|page=163|plainurl=yes}} |title=[[Natural History (Pliny)|Naturalis Historiae]] |last=Pliny the Elder |volume=Book 37 |page=115 |chapter=chapter 7}}</ref> The name is probably derived from the town [[Chalcedon]] in [[Asia Minor]].<ref>{{cite book| first=Erika |last=Zwierlein-Diehl|title=Antike Gemmen und ihr Nachleben|location=Berlin |publisher =Verlag [[Walter de Gruyter]]|date=2007|at=S. 307 |url={{google books|plainurl=yes|id=OtaMtKzaKR8C|page=307}}}} According to the [[OED]] a connection with the town of Chalcedon is "very doubtful":{{OEtymD|Chalcedony}}</ref> The Greek word ''khalkedon'' (χαλκηδών) also appears in the [[Book of Revelation]] (Apc 21,19). It is a [[hapax legomenon]] found nowhere else, so it is hard to tell whether the [[precious gem]] mentioned in the Bible is the same mineral known by this name today.<ref>{{cite book |title=The International Standard Bible Encyclopaedia |editor=James Orr |publisher=The Howard-Severance company |year=1915 |chapter=''Chalkēdōn'' |page=2859 |url=https://books.google.com/?id=CqPNAAAAMAAJ&pg=PA2859&dq=chalcedony+Chalkedon#v=onepage&q=chalcedony%20Chalkedon&f=false}}</ref>
[[File:Mogánite-798422.jpg|upright=0.8|thumb|A rare [[Morocco|Morroccan]] [[pseudomorph]] of a spiral [[Turritella]]-like snail that has been replaced by chalcedony]]
== Varieties ==
Chalcedony occurs in a wide range of varieties. Many semi-precious [[gemstone]]s are in fact forms of chalcedony. The more notable varieties of chalcedony are as follows:
===Agate===
[[File:Quartz - Agateplate, redbrown-white.jpg|thumb|left|180px|Agate]]
'''[[Agate]]''' is a variety of chalcedony characterized by either transparency or color patterns, such as multi-colored curved or angular banding. Opaque varieties are sometimes referred to as [[jasper]].<ref name="gemsociety">{{Cite web |url=http://www.gemsociety.org/article/chalcedony-jewelry-and-gemstone-information/ |title=Chalcedony Gemological Information |publisher=International Gem Society (IGS) |access-date=16 January 2015 |deadurl=no |archiveurl=https://web.archive.org/web/20150207162538/http://www.gemsociety.org/article/chalcedony-jewelry-and-gemstone-information/ |archivedate=7 February 2015 |df= }}</ref> Fire agate shows iridescent phenomena on a brown background; iris agate shows exceptional [[iridescence]] when light (especially pinpointed light) is shone through the stone. Landscape agate is chalcedony with a number of different mineral impurities making the stone resemble landscapes.<ref name="cibjo">{{Cite web |url=http://www.cibjo.org/index.php?option=com_content&view=article&id=55&Itemid=32 |title=Retailers' Reference Guide: Diamonds, Cemstones, Pearls and Precious Metals |author=CIBJO member laboratories |date=May 2009 |publisher=CIBJO (The World Jewellery Federation, international federation of all national trade organizations and gemological laboratories) |location=Bern, Switzerland }}</ref>
{{clear}}
===Aventurine===
[[File:Aventurine.jpg|thumb|left|180px|Aventurine (''Unknown scale'')]]
'''[[Aventurine]]''' is a form of quartz, characterised by its translucency and the presence of platy [[mineral]] [[inclusion (mineral)|inclusion]]s that give a shimmering or glistening effect termed [[aventurescence]]. Chrome-bearing [[fuchsite]] (a variety of [[muscovite]] [[mica]]) is the classic inclusion, and gives a silvery green or blue sheen. Oranges and browns are attributed to [[hematite]] or [[goethite]].
{{clear}}
===Carnelian===
[[File:carnelian sard (mineral specimen).jpg|thumb|left|180px|Carnelian]]
'''[[Carnelian]]''' (also spelled cornelian) is a clear-to-translucent reddish-brown variety of chalcedony. Its hue may vary from a pale orange, to an intense almost-black coloration. Similar to carnelian is [[carnelian|sard]], which is brown rather than red.
{{clear}}
===Chrysoprase===
[[File:Chryzopras Polsko.jpg|thumb|left|180px|Chrysoprase]]
'''[[Chrysoprase]]''' (also spelled chrysophrase) is a green variety of chalcedony, which has been colored by [[Nickel(II) oxide|nickel oxide]]. (The darker varieties of chrysoprase are also referred to as prase. However, the term prase is also used to describe green [[quartz]], and to a certain extent is a color-descriptor, rather than a rigorously defined mineral variety.)
Blue-colored chalcedony is sometimes referred to as "blue chrysoprase" if the color is sufficiently rich, though it derives its color from the presence of [[copper]] and is largely unrelated to nickel-bearing chrysoprase.
{{clear}}
===Heliotrope===
[[File:Quarz - Heliotrop (Blutjaspis).JPG|thumb|left|180px|Heliotrope, or bloodstone]]
'''[[Heliotrope (mineral)|Heliotrope]]''' is a green variety of chalcedony, containing red inclusions of [[iron oxide]] that resemble drops of [[blood]], giving heliotrope its alternative name of bloodstone. In a similar variety, the spots are yellow instead, known as plasma.
{{clear}}
===Moss agate===
[[File:mossagate.pebble.750pix.jpg|thumb|left|180px|Tree agate]]
'''[[Moss agate]]''' contains green filament-like inclusions, giving it the superficial appearance of [[moss]] or [[blue cheese]]. There is also tree agate which is similar to moss agate except it is solid white with green filaments whereas moss agate usually has a transparent background, so the "moss" appears in 3D. It is not a true form of agate, as it lacks agate's defining feature of concentric banding.
{{clear}}
===Mtorolite===
[[File:Mtorolite zimbabwe trimmed.jpg|thumb|left|180px|Mtorolite]]
'''[[Mtorolite]]''' is a green variety of chalcedony, which has been colored by [[chromium]]. Also known as [[chrome chalcedony]], it is principally found in [[Zimbabwe]].
{{clear}}
===Onyx===
[[File:Agate-Quartz-49959.jpg|thumb|left|180px|Onyx]]
'''[[Onyx]]''' is a variant of agate with black and white banding. Similarly, agate with brown, orange, red and white banding is known as [[sardonyx]].
{{clear}}
== History ==
[[File:Titus cameo.jpg|right|thumb|Chalcedony [[Cameo (carving)|cameo]] of [[Titus]] head, 2nd Century AD]]
As early as the [[Bronze Age]] chalcedony was in use in the [[Mediterranean]] region; for example, on [[Minoan civilization|Minoan]] [[Crete]] at the Palace of [[Knossos]], chalcedony [[Minoan seal-stones|seal]]s have been recovered dating to circa 1800 [[Before Christ|BC]].<ref>{{Cite web |url=http://www.themodernantiquarian.com/site/10854/knossos.html#fieldnotes |title=Knossos fieldnotes |last=Hogan |first=C. Michael |date=2007 |publisher=Modern Antiquarian |deadurl=no |archiveurl=https://web.archive.org/web/20160409225800/http://www.themodernantiquarian.com/site/10854/knossos.html#fieldnotes |archivedate=2016-04-09 |df= }}</ref> People living along the [[Central Asia]]n trade routes used various forms of chalcedony, including [[carnelian]], to carve [[Intaglio (jewellery)|intaglios]], ring bezels (the upper faceted portion of a gem projecting from the ring setting), and beads that show strong Greco-Roman influence.
Fine examples of first century objects made from chalcedony, possibly [[Kushan]], were found in recent years at [[Tillya-tepe]] in north-western [[Afghanistan]].<ref>Section 12 of the translation of ''Weilue'' - a 3rd-century Chinese text by John Hill under "carnelian" and note 12.12 (17)A. Also see Afghanistan's exhibition:[http://www.farlang.com/profiles/afghanistan-museum-kabul/product.2009-03-24.6644617360 Intaglio with depiction of a griffin, Chalcedony, 4th century BC, Afghanistan] {{webarchive |url=https://web.archive.org/web/20120225063934/http://www.farlang.com/profiles/afghanistan-museum-kabul/product.2009-03-24.6644617360 |date=February 25, 2012 }}
</ref> Hot wax would not stick to it so it was often used to make [[Seal (device)|seal]] impressions.
The term ''chalcedony'' is derived from the name of the ancient Greek town Chalkedon in [[Asia Minor]], in modern English usually spelled [[Chalcedon]], today the [[Kadıköy]] district of [[Istanbul]].
[[File:ChalcedonyKnifeNPS.jpg|left|thumb|300px|Chalcedony knife, AD 1000-1200]]
According to tradition, at least three varieties of chalcedony were used in the Jewish High Priest's Breastplate. (Jewish tradition states that Moses' brother Aaron wore the Breastplate, with inscribed gems representing the twelve tribes of Israel). The Breastplate supposedly included ''jasper'', ''chrysoprase'' and ''sardonyx'', and there is some debate as to whether other ''agates'' were also used.
In the 19th century, [[Idar-Oberstein]], Germany, became the world's largest chalcedony processing center, working mostly on agates. Most of these agates were from Latin America, in particular Brazil. Originally the agate carving industry around Idar and Oberstein was driven by local deposits that were mined in the 15th century.<ref name="streeter1">{{Cite book |title=Precious Stones and Gems |last=Streeter |first=Edwin |date=1898 |page=237}}</ref> Several factors contributed to the re-emergence of Idar-Oberstein as agate center of the world: ships brought agate nodules back as ballast, thus providing extremely cheap transport. In addition, cheap labor and a superior knowledge of chemistry allowed them to dye the agates in any color with processes that were kept secret. Each mill in Idar-Oberstein had four or five grindstones. These were of red sandstone, obtained from Zweibrücken; and two men ordinarily worked together at the same stone.<ref name="streeter1" />
== Geochemistry==
[[File:Sumin chalcedony mouse.jpg|thumb|chalcedony mouse, by [[Avenir Sumin]]]]
===Structure===
Chalcedony was once thought to be a fibrous variety of cryptocrystalline [[quartz]].<ref>{{Cite web |url=http://www.mindat.org/min-960.html |title=Chalcedony mineral information and data |website=www.mindat.org |deadurl=no |archiveurl=https://web.archive.org/web/20060821000434/http://www.mindat.org/min-960.html |archivedate=2006-08-21 |df= }}</ref> More recently however, it has been shown to also contain a [[monoclinic]] polymorph of quartz, known as [[moganite]].<ref name="heany_1994" /> The fraction, by mass, of moganite within a typical chalcedony sample may vary from less than 5% to over 20%.<ref name="heany_1992">{{Cite journal |last=Heaney |first=Peter J. |last2=Post |first2=Jeffrey E. |date=24 January 1992 |title=The Widespread Distribution of a Novel Silica Polymorph in Microcrystalline Quartz Varieties |journal=Science |series=New Series |volume=255 |issue=5043 |pages=441–443 |doi=10.1126/science.255.5043.4 |pmid=17842895 |JSTOR=2876012}}</ref> The existence of moganite was once regarded as dubious, but it is now officially recognised by the [[International Mineralogical Association]].<ref>{{Cite journal |last=Origlieri |first=Marcus |date=January 1994 |title=Moganite: a New Mineral -- Not! |url=http://fgms.home.att.net/moganite.htm |journal=Lithosphere |archive-url=https://web.archive.org/web/20080309094336/http://fgms.home.att.net/moganite.htm |archive-date=March 9, 2008 }}</ref><ref>{{Cite journal |last=Nickel |first=Ernest H. |last2=Nichols |first2=Monte C. |date=16 May 2008 |title=IMA/CNMNC List of Mineral Names |url=http://www.geo.vu.nl/users/ima-cnmmn/MINERALlist.pdf |dead-url=yes |journal=Materials Data |archive-url=https://web.archive.org/web/20080530134400/http://www.geo.vu.nl/users/ima-cnmmn/MINERALlist.pdf |archive-date=2008-05-30 |access-date=2008-06-29}}></ref>
===Solubility===
Chalcedony is more [[soluble]] than quartz under low-temperature conditions, despite the two minerals being chemically identical. This is thought to be because chalcedony is extremely finely grained (cryptocrystalline), and so has a very high surface area to volume ratio. {{Citation needed|date=February 2007}} It has also been suggested that the higher solubility is due to the moganite component.<ref name="heany_1992" />
====Solubility of quartz and chalcedony in pure water====
This table gives equilibrium concentrations of total dissolved silicon as calculated by ''PHREEQC'' (PH REdox EQuilibrium (in C language, USGS)) using the llnl.dat database.{{Citation needed|date=December 2009}}
{| class="wikitable" style="margin:auto"
|-
! Temperature
! Quartz solubility (mg/L)
! Chalcedony solubility (mg/L)
|-
! 0.01 °C
| 0.68
| 1.34
|-
! 25.0 °C
| 2.64
| 4.92
|-
! 50.0 °C
| 6.95
| 12.35
|-
! 75.0 °C
| 14.21
| 24.23
|-
! 100.0 °C
| 24.59
| 40.44
|}
== See also ==
* [[List of minerals]]
==References==
{{reflist}}
==External links==
{{Wikisource1911Enc|Chalcedony}}
*{{commonscat-inline}}
*[http://www.mindat.org/min-960.html Mindat: mineralogical data Chalcedony]
*[http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/sp14-95/chalcedony.html USGS: US Chalcedony locations]
{{Silica minerals}}
[[Category:Chalcedony|*]]
[[Category:Lithics]]
[[Category:Trigonal minerals]]' |
New page wikitext, after the edit (new_wikitext) | '{{short description|Microcrystalline varieties of quartz, may contain moganite as well}}
{{Infobox mineral
| name = Chalcedony
| category = [[Oxide minerals]], [[quartz]] group
| image = Quartz-83325.jpg
| imagesize = 260px
| caption = aaaaaaaaaaaaaaaaaaaaaaaaaaaa
| formula = [[Silica]] (silicon dioxide, {{Chem|Si|O|2}})
| molweight = 60 g/mol
| color = Various
| habit =
| system = Trigonal or monoclinic
| twinning =
| cleavage = Absent
| fracture = Uneven, splintery, conchoidal
| mohs = 6 - 7
| luster = Waxy, vitreous, dull, greasy, silky
| refractive =
| opticalprop =
| birefringence =
| pleochroism =
| streak = White
| gravity = 2.59 - 2.61
| density =
| melt =
| fusibility =
| diagnostic =
| solubility =
| diaphaneity = Translucent
| other =
| references = <ref>{{Cite book |title=Minerals of the World |last=Duda |first=Rudolf |last2=Rejl |first2=Lubos |date=1990 |publisher=Arch Cape Press}}</ref>
}}
'''Chalcedony''' ({{IPAc-en|pron|k|æ|l|ˈ|s|ɛ|d|ə|n|i}}) is a [[cryptocrystalline]] form of [[silica]], composed of very fine intergrowths of [[quartz]] and [[moganite]].<ref name="heany_1994">{{Cite book |title=Silica: Physical Behavior, geochemistry and materials applications |last=Heaney |first=Peter J. |date=1994 |editor-last=Heaney |editor-first=P. J. |series=Reviews in Mineralogy |volume=29 |pages=1–40 |chapter=Structure and Chemistry of the low-pressure silica polymorphs |editor-last2=Prewitt |editor-first2=C. T. |editor-last3=Gibbs |editor-first3=G. V.}}</ref> These are both silica [[mineral]]s, but they differ in that quartz has a [[trigonal]] crystal structure, while moganite is [[monoclinic]]. Chalcedony's standard [[chemical structure]] (based on the chemical structure of quartz) is SiO<sub>2</sub> (silicon dioxide).
Chalcedony has a waxy luster, and may be semitransparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black. The color of chalcedony sold commercially is often enhanced by dyeing or heating.<ref name="gemsociety" />
The name ''chalcedony'' comes from the [[Latin]] ''chalcedonius'' (alternatively spelled ''calchedonius''). The name appears in [[Pliny the Elder]]'s ''[[Naturalis Historia]]'' as a term for a translucid kind of [[Jaspis]].<ref>{{Cite book |chapterurl={{google books|id=oHlGAAAAYAAJ|page=163|plainurl=yes}} |title=[[Natural History (Pliny)|Naturalis Historiae]] |last=Pliny the Elder |volume=Book 37 |page=115 |chapter=chapter 7}}</ref> The name is probably derived from the town [[Chalcedon]] in [[Asia Minor]].<ref>{{cite book| first=Erika |last=Zwierlein-Diehl|title=Antike Gemmen und ihr Nachleben|location=Berlin |publisher =Verlag [[Walter de Gruyter]]|date=2007|at=S. 307 |url={{google books|plainurl=yes|id=OtaMtKzaKR8C|page=307}}}} According to the [[OED]] a connection with the town of Chalcedon is "very doubtful":{{OEtymD|Chalcedony}}</ref> The Greek word ''khalkedon'' (χαλκηδών) also appears in the [[Book of Revelation]] (Apc 21,19). It is a [[hapax legomenon]] found nowhere else, so it is hard to tell whether the [[precious gem]] mentioned in the Bible is the same mineral known by this name today.<ref>{{cite book |title=The International Standard Bible Encyclopaedia |editor=James Orr |publisher=The Howard-Severance company |year=1915 |chapter=''Chalkēdōn'' |page=2859 |url=https://books.google.com/?id=CqPNAAAAMAAJ&pg=PA2859&dq=chalcedony+Chalkedon#v=onepage&q=chalcedony%20Chalkedon&f=false}}</ref>
[[File:Mogánite-798422.jpg|upright=0.8|thumb|A rare [[Morocco|Morroccan]] [[pseudomorph]] of a spiral [[Turritella]]-like snail that has been replaced by chalcedony]]
== Varieties ==
Chalcedony occurs in a wide range of varieties. Many semi-precious [[gemstone]]s are in fact forms of chalcedony. The more notable varieties of chalcedony are as follows:
===Agate===
[[File:Quartz - Agateplate, redbrown-white.jpg|thumb|left|180px|Agate]]
'''[[Agate]]''' is a variety of chalcedony characterized by either transparency or color patterns, such as multi-colored curved or angular banding. Opaque varieties are sometimes referred to as [[jasper]].<ref name="gemsociety">{{Cite web |url=http://www.gemsociety.org/article/chalcedony-jewelry-and-gemstone-information/ |title=Chalcedony Gemological Information |publisher=International Gem Society (IGS) |access-date=16 January 2015 |deadurl=no |archiveurl=https://web.archive.org/web/20150207162538/http://www.gemsociety.org/article/chalcedony-jewelry-and-gemstone-information/ |archivedate=7 February 2015 |df= }}</ref> Fire agate shows iridescent phenomena on a brown background; iris agate shows exceptional [[iridescence]] when light (especially pinpointed light) is shone through the stone. Landscape agate is chalcedony with a number of different mineral impurities making the stone resemble landscapes.<ref name="cibjo">{{Cite web |url=http://www.cibjo.org/index.php?option=com_content&view=article&id=55&Itemid=32 |title=Retailers' Reference Guide: Diamonds, Cemstones, Pearls and Precious Metals |author=CIBJO member laboratories |date=May 2009 |publisher=CIBJO (The World Jewellery Federation, international federation of all national trade organizations and gemological laboratories) |location=Bern, Switzerland }}</ref>
{{clear}}
===Aventurine===
[[File:Aventurine.jpg|thumb|left|180px|Aventurine (''Unknown scale'')]]
'''[[Aventurine]]''' is a form of quartz, characterised by its translucency and the presence of platy [[mineral]] [[inclusion (mineral)|inclusion]]s that give a shimmering or glistening effect termed [[aventurescence]]. Chrome-bearing [[fuchsite]] (a variety of [[muscovite]] [[mica]]) is the classic inclusion, and gives a silvery green or blue sheen. Oranges and browns are attributed to [[hematite]] or [[goethite]].
{{clear}}
===Carnelian===
[[File:carnelian sard (mineral specimen).jpg|thumb|left|180px|Carnelian]]
'''[[Carnelian]]''' (also spelled cornelian) is a clear-to-translucent reddish-brown variety of chalcedony. Its hue may vary from a pale orange, to an intense almost-black coloration. Similar to carnelian is [[carnelian|sard]], which is brown rather than red.
{{clear}}
===Chrysoprase===
[[File:Chryzopras Polsko.jpg|thumb|left|180px|Chrysoprase]]
'''[[Chrysoprase]]''' (also spelled chrysophrase) is a green variety of chalcedony, which has been colored by [[Nickel(II) oxide|nickel oxide]]. (The darker varieties of chrysoprase are also referred to as prase. However, the term prase is also used to describe green [[quartz]], and to a certain extent is a color-descriptor, rather than a rigorously defined mineral variety.)
Blue-colored chalcedony is sometimes referred to as "blue chrysoprase" if the color is sufficiently rich, though it derives its color from the presence of [[copper]] and is largely unrelated to nickel-bearing chrysoprase.
{{clear}}
===Heliotrope===
[[File:Quarz - Heliotrop (Blutjaspis).JPG|thumb|left|180px|Heliotrope, or bloodstone]]
'''[[Heliotrope (mineral)|Heliotrope]]''' is a green variety of chalcedony, containing red inclusions of [[iron oxide]] that resemble drops of [[blood]], giving heliotrope its alternative name of bloodstone. In a similar variety, the spots are yellow instead, known as plasma.
{{clear}}
===Moss agate===
[[File:mossagate.pebble.750piax.jpg|thumb|left|180px|Tree agate]]
'''[[Moss agate]]''' contains green filament-like inclusions, giving it the superficial appearance of [[moss]] or [[blue cheese]]. There is also tree agate which is similar to moss agate except it is solid white with green filaments whereas moss agate usually has a transparent background, so the "moss" appears in 3D. It is not a true form of agate, as it lacks agate's defining feature of concentric banding.
{{clear}}
===Mtorolite===
[[File:Mtorolite zimbabwe trimmed.jpg|thumb|left|180px|Mtorolite]]
'''[[Mtorolite]]''' is a green variety of chalcedony, which has been colored by [[chromium]]. Also known as [[chrome chalcedony]], it is principally found in [[Zimbabwe]].
{{clear}}
===Onyx===
[[File:Agate-Quartz-49959.jpg|thumb|left|180px|Onyx]]
'''[[Onyx]]''' is a variant of agate with black and white banding. Similarly, agate with brown, orange, red and white banding is known as [[sardonyx]].
{{clear}}
== History ==
[[File:Titus cameo.jpg|right|thumb|Chalcedony [[Cameo (carving)|cameo]] of [[Titus]] head, 2nd Century AD]]
As early as the [[Bronze Age]] chalcedony was in use in the [[Mediterranean]] region; for example, on [[Minoan civilization|Minoan]] [[Crete]] at the Palace of [[Knossos]], chalcedony [[Minoan seal-stones|seal]]s have been recovered dating to circa 1800 [[Before Christ|BC]].<ref>{{Cite web |url=http://www.themodernantiquarian.com/site/10854/knossos.html#fieldnotes |title=Knossos fieldnotes |last=Hogan |first=C. Michael |date=2007 |publisher=Modern Antiquarian |deadurl=no |archiveurl=https://web.archive.org/web/20160409225800/http://www.themodernantiquarian.com/site/10854/knossos.html#fieldnotes |archivedate=2016-04-09 |df= }}</ref> People living along the [[Central Asia]]n trade routes used various forms of chalcedony, including [[carnelian]], to carve [[Intaglio (jewellery)|intaglios]], ring bezels (the upper faceted portion of a gem projecting from the ring setting), and beads that show strong Greco-Roman influence.
Fine examples of first century objects made from chalcedony, possibly [[Kushan]], were found in recent years at [[Tillya-tepe]] in north-western [[Afghanistan]].<ref>Section 12 of the translation of ''Weilue'' - a 3rd-century Chinese text by John Hill under "carnelian" and note 12.12 (17)A. Also see Afghanistan's exhibition:[http://www.farlang.com/profiles/afghanistan-museum-kabul/product.2009-03-24.6644617360 Intaglio with depiction of a griffin, Chalcedony, 4th century BC, Afghanistan] {{webarchive |url=https://web.archive.org/web/20120225063934/http://www.farlang.com/profiles/afghanistan-museum-kabul/product.2009-03-24.6644617360 |date=February 25, 2012 }}
</ref> Hot wax would not stick to it so it was often used to make [[Seal (device)|seal]] impressions.
The term ''chalcedony'' is derived from the name of the ancient Greek town Chalkedon in [[Asia Minor]], in modern English usually spelled [[Chalcedon]], today the [[Kadıköy]] district of [[Istanbul]].
[[File:ChalcedonyKnifeNPS.jpg|left|thumb|300px|Chalcedony knife, AD 1000-1200]]
According to tradition, at least three varieties of chalcedony were used in the Jewish High Priest's Breastplate. (Jewish tradition states that Moses' brother Aaron wore the Breastplate, with inscribed gems representing the twelve tribes of Israel). The Breastplate supposedly included ''jasper'', ''chrysoprase'' and ''sardonyx'', and there is some debate as to whether other ''agates'' were also used.
In the 19th century, [[Idar-Oberstein]], Germany, became the world's largest chalcedony processing center, working mostly on agates. Most of these agates were from Latin America, in particular Brazil. Originally the agate carving industry around Idar and Oberstein was driven by local deposits that were mined in the 15th century.<ref name="streeter1">{{Cite book |title=Precious Stones and Gems |last=Streeter |first=Edwin |date=1898 |page=237}}</ref> Several factors contributed to the re-emergence of Idar-Oberstein as agate center of the world: ships brought agate nodules back as ballast, thus providing extremely cheap transport. In addition, cheap labor and a superior knowledge of chemistry allowed them to dye the agates in any color with processes that were kept secret. Each mill in Idar-Oberstein had four or five grindstones. These were of red sandstone, obtained from Zweibrücken; and two men ordinarily worked together at the same stone.<ref name="streeter1" />
== Geochemistry==
[[File:Sumin chalcedony mouse.jpg|thumb|chalcedony mouse, by [[Avenir Sumin]]]]
===Structure===
Chalcedony was once thought to be a fibrous variety of cryptocrystalline [[quartz]].<ref>{{Cite web |url=http://www.mindat.org/min-960.html |title=Chalcedony mineral information and data |website=www.mindat.org |deadurl=no |archiveurl=https://web.archive.org/web/20060821000434/http://www.mindat.org/min-960.html |archivedate=2006-08-21 |df= }}</ref> More recently however, it has been shown to also contain a [[monoclinic]] polymorph of quartz, known as [[moganite]].<ref name="heany_1994" /> The fraction, by mass, of moganite within a typical chalcedony sample may vary from less than 5% to over 20%.<ref name="heany_1992">{{Cite journal |last=Heaney |first=Peter J. |last2=Post |first2=Jeffrey E. |date=24 January 1992 |title=The Widespread Distribution of a Novel Silica Polymorph in Microcrystalline Quartz Varieties |journal=Science |series=New Series |volume=255 |issue=5043 |pages=441–443 |doi=10.1126/science.255.5043.4 |pmid=17842895 |JSTOR=2876012}}</ref> The existence of moganite was once regarded as dubious, but it is now officially recognised by the [[International Mineralogical Association]].<ref>{{Cite journal |last=Origlieri |first=Marcus |date=January 1994 |title=Moganite: a New Mineral -- Not! |url=http://fgms.home.att.net/moganite.htm |journal=Lithosphere |archive-url=https://web.archive.org/web/20080309094336/http://fgms.home.att.net/moganite.htm |archive-date=March 9, 2008 }}</ref><ref>{{Cite journal |last=Nickel |first=Ernest H. |last2=Nichols |first2=Monte C. |date=16 May 2008 |title=IMA/CNMNC List of Mineral Names |url=http://www.geo.vu.nl/users/ima-cnmmn/MINERALlist.pdf |dead-url=yes |journal=Materials Data |archive-url=https://web.archive.org/web/20080530134400/http://www.geo.vu.nl/users/ima-cnmmn/MINERALlist.pdf |archive-date=2008-05-30 |access-date=2008-06-29}}></ref>
===Solubility===
Chalcedony is more [[soluble]] than quartz under low-temperature conditions, despite the two minerals being chemically identical. This is thought to be because chalcedony is extremely finely grained (cryptocrystalline), and so has a very high surface area to volume ratio. {{Citation needed|date=February 2007}} It has also been suggested that the higher solubility is due to the moganite component.<ref name="heany_1992" />
====Solubility of quartz and chalcedony in pure water====
This table gives equilibrium concentrations of total dissolved silicon as calculated by ''PHREEQC'' (PH REdox EQuilibrium (in C language, USGS)) using the llnl.dat database.{{Citation needed|date=December 2009}}
{| class="wikitable" style="margin:auto"
|-
! Temperature
! Quartz solubility (mg/L)
! Chalcedony solubility (mg/L)
|-
! 0.01 °C
| 0.68
| 1.34
|-
! 25.0 °C
| 2.64
| 4.92
|-
! 50.0 °C
| 6.95
| 12.35
|-
! 75.0 °C
| 14.21
| 24.23
|-
! 100.0 °C
| 24.59
| 40.44
|}
== See also ==
* [[List of minerals]]
==References==
{{reflist}}
==External links==
{{Wikisource1911Enc|Chalcedony}}
*{{commonscat-inline}}
*[http://www.mindat.org/min-960.html Mindat: mineralogical data Chalcedony]
*[http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/sp14-95/chalcedony.html USGS: US Chalcedony locations]
{{Silica minerals}}
[[Category:Chalcedony|*]]
[[Category:Lithics]]
[[Category:Trigonal minerals]]' |
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===Moss agate===
-[[File:mossagate.pebble.750pix.jpg|thumb|left|180px|Tree agate]]
+[[File:mossagate.pebble.750piax.jpg|thumb|left|180px|Tree agate]]
'''[[Moss agate]]''' contains green filament-like inclusions, giving it the superficial appearance of [[moss]] or [[blue cheese]]. There is also tree agate which is similar to moss agate except it is solid white with green filaments whereas moss agate usually has a transparent background, so the "moss" appears in 3D. It is not a true form of agate, as it lacks agate's defining feature of concentric banding.
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Parsed HTML source of the new revision (new_html) | '<div class="mw-parser-output"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Microcrystalline varieties of quartz, may contain moganite as well</div>
<table class="infobox" style="width:22em"><tbody><tr><th colspan="2" style="text-align:center;font-size:125%;font-weight:bold;color:black; background-color: #8BAFDA">Chalcedony</th></tr><tr><td colspan="2" style="text-align:center"><a href="/enwiki/wiki/File:Quartz-83325.jpg" class="image"><img alt="Quartz-83325.jpg" src="/upwiki/wikipedia/commons/thumb/5/50/Quartz-83325.jpg/260px-Quartz-83325.jpg" decoding="async" width="260" height="152" srcset="/upwiki/wikipedia/commons/thumb/5/50/Quartz-83325.jpg/390px-Quartz-83325.jpg 1.5x, /upwiki/wikipedia/commons/thumb/5/50/Quartz-83325.jpg/520px-Quartz-83325.jpg 2x" data-file-width="800" data-file-height="469" /></a><div>aaaaaaaaaaaaaaaaaaaaaaaaaaaa</div></td></tr><tr><th colspan="2" style="text-align:center;color:black; background-color: #8BAFDA">General</th></tr><tr><th scope="row">Category</th><td><a href="/enwiki/wiki/Oxide_minerals" title="Oxide minerals">Oxide minerals</a>, <a href="/enwiki/wiki/Quartz" title="Quartz">quartz</a> group</td></tr><tr><th scope="row"><a href="/enwiki/wiki/Chemical_formula" title="Chemical formula">Formula</a><br /><style data-mw-deduplicate="TemplateStyles:r886047488">.mw-parser-output .nobold{font-weight:normal}</style><span class="nobold">(repeating unit)</span></th><td><a href="/enwiki/wiki/Silica" class="mw-redirect" title="Silica">Silica</a> (silicon dioxide, <span class="chemf nowrap">SiO<span style="display:inline-block;margin-bottom:-0.3em;vertical-align:-0.4em;line-height:1em;font-size:80%;text-align:left"><sup style="font-size:inherit;line-height:inherit;vertical-align:baseline"></sup><br /><sub style="font-size:inherit;line-height:inherit;vertical-align:baseline">2</sub></span></span>)</td></tr><tr><th scope="row"><a href="/enwiki/wiki/Crystal_system" title="Crystal system">Crystal system</a></th><td>Trigonal or monoclinic</td></tr><tr><th colspan="2" style="text-align:center;color:black; background-color: #8BAFDA">Identification</th></tr><tr><th scope="row"><a href="/enwiki/wiki/Formula_mass" class="mw-redirect" title="Formula mass">Formula mass</a></th><td>60 g/mol</td></tr><tr><th scope="row">Color</th><td>Various</td></tr><tr><th scope="row"><a href="/enwiki/wiki/Cleavage_(crystal)" title="Cleavage (crystal)">Cleavage</a></th><td>Absent</td></tr><tr><th scope="row"><a href="/enwiki/wiki/Fracture_(mineralogy)" title="Fracture (mineralogy)">Fracture</a></th><td>Uneven, splintery, conchoidal</td></tr><tr><th scope="row"><a href="/enwiki/wiki/Mohs_scale_of_mineral_hardness" title="Mohs scale of mineral hardness">Mohs scale</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886047488"/><span class="nobold">hardness</span></th><td>6 - 7</td></tr><tr><th scope="row"><a href="/enwiki/wiki/Lustre_(mineralogy)" title="Lustre (mineralogy)">Luster</a></th><td>Waxy, vitreous, dull, greasy, silky</td></tr><tr><th scope="row"><a href="/enwiki/wiki/Streak_(mineralogy)" title="Streak (mineralogy)">Streak</a></th><td>White</td></tr><tr><th scope="row"><a href="/enwiki/wiki/Transparency_and_translucency" title="Transparency and translucency">Diaphaneity</a></th><td>Translucent</td></tr><tr><th scope="row"><a href="/enwiki/wiki/Specific_gravity" title="Specific gravity">Specific gravity</a></th><td>2.59 - 2.61</td></tr><tr><th scope="row">References</th><td><sup id="cite_ref-1" class="reference"><a href="#cite_note-1">[1]</a></sup></td></tr></tbody></table>
<p><b>Chalcedony</b> (<span class="nowrap"><small> </small><span class="IPA nopopups noexcerpt"><a href="/enwiki/wiki/Help:IPA/English" title="Help:IPA/English">/<span style="border-bottom:1px dotted"><span title="'k' in 'kind'">k</span><span title="/æ/: 'a' in 'bad'">æ</span><span title="'l' in 'lie'">l</span><span title="/ˈ/: primary stress follows">ˈ</span><span title="'s' in 'sigh'">s</span><span title="/ɛ/: 'e' in 'dress'">ɛ</span><span title="'d' in 'dye'">d</span><span title="/ə/: 'a' in 'about'">ə</span><span title="'n' in 'nigh'">n</span><span title="/i/: 'y' in 'happy'">i</span></span>/</a></span></span>) is a <a href="/enwiki/wiki/Cryptocrystalline" title="Cryptocrystalline">cryptocrystalline</a> form of <a href="/enwiki/wiki/Silica" class="mw-redirect" title="Silica">silica</a>, composed of very fine intergrowths of <a href="/enwiki/wiki/Quartz" title="Quartz">quartz</a> and <a href="/enwiki/wiki/Moganite" title="Moganite">moganite</a>.<sup id="cite_ref-heany_1994_2-0" class="reference"><a href="#cite_note-heany_1994-2">[2]</a></sup> These are both silica <a href="/enwiki/wiki/Mineral" title="Mineral">minerals</a>, but they differ in that quartz has a <a href="/enwiki/wiki/Trigonal" class="mw-redirect" title="Trigonal">trigonal</a> crystal structure, while moganite is <a href="/enwiki/wiki/Monoclinic" class="mw-redirect" title="Monoclinic">monoclinic</a>. Chalcedony's standard <a href="/enwiki/wiki/Chemical_structure" title="Chemical structure">chemical structure</a> (based on the chemical structure of quartz) is SiO<sub>2</sub> (silicon dioxide).
</p><p>Chalcedony has a waxy luster, and may be semitransparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black. The color of chalcedony sold commercially is often enhanced by dyeing or heating.<sup id="cite_ref-gemsociety_3-0" class="reference"><a href="#cite_note-gemsociety-3">[3]</a></sup>
</p><p>The name <i>chalcedony</i> comes from the <a href="/enwiki/wiki/Latin" title="Latin">Latin</a> <i>chalcedonius</i> (alternatively spelled <i>calchedonius</i>). The name appears in <a href="/enwiki/wiki/Pliny_the_Elder" title="Pliny the Elder">Pliny the Elder</a>'s <i><a href="/enwiki/wiki/Naturalis_Historia" class="mw-redirect" title="Naturalis Historia">Naturalis Historia</a></i> as a term for a translucid kind of <a href="/enwiki/wiki/Jaspis" class="mw-redirect" title="Jaspis">Jaspis</a>.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4">[4]</a></sup> The name is probably derived from the town <a href="/enwiki/wiki/Chalcedon" title="Chalcedon">Chalcedon</a> in <a href="/enwiki/wiki/Asia_Minor" class="mw-redirect" title="Asia Minor">Asia Minor</a>.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5">[5]</a></sup> The Greek word <i>khalkedon</i> (χαλκηδών) also appears in the <a href="/enwiki/wiki/Book_of_Revelation" title="Book of Revelation">Book of Revelation</a> (Apc 21,19). It is a <a href="/enwiki/wiki/Hapax_legomenon" title="Hapax legomenon">hapax legomenon</a> found nowhere else, so it is hard to tell whether the <a href="/enwiki/wiki/Precious_gem" class="mw-redirect" title="Precious gem">precious gem</a> mentioned in the Bible is the same mineral known by this name today.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6">[6]</a></sup>
</p>
<div class="thumb tright"><div class="thumbinner" style="width:182px;"><a href="/enwiki/wiki/File:Mog%C3%A1nite-798422.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/3/3c/Mog%C3%A1nite-798422.jpg/180px-Mog%C3%A1nite-798422.jpg" decoding="async" width="180" height="291" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/3/3c/Mog%C3%A1nite-798422.jpg/270px-Mog%C3%A1nite-798422.jpg 1.5x, /upwiki/wikipedia/commons/thumb/3/3c/Mog%C3%A1nite-798422.jpg/360px-Mog%C3%A1nite-798422.jpg 2x" data-file-width="634" data-file-height="1024" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Mog%C3%A1nite-798422.jpg" class="internal" title="Enlarge"></a></div>A rare <a href="/enwiki/wiki/Morocco" title="Morocco">Morroccan</a> <a href="/enwiki/wiki/Pseudomorph" title="Pseudomorph">pseudomorph</a> of a spiral <a href="/enwiki/wiki/Turritella" title="Turritella">Turritella</a>-like snail that has been replaced by chalcedony</div></div></div>
<div id="toc" class="toc"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none" /><div class="toctitle" lang="en" dir="ltr"><h2>Contents</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="#Varieties"><span class="tocnumber">1</span> <span class="toctext">Varieties</span></a>
<ul>
<li class="toclevel-2 tocsection-2"><a href="#Agate"><span class="tocnumber">1.1</span> <span class="toctext">Agate</span></a></li>
<li class="toclevel-2 tocsection-3"><a href="#Aventurine"><span class="tocnumber">1.2</span> <span class="toctext">Aventurine</span></a></li>
<li class="toclevel-2 tocsection-4"><a href="#Carnelian"><span class="tocnumber">1.3</span> <span class="toctext">Carnelian</span></a></li>
<li class="toclevel-2 tocsection-5"><a href="#Chrysoprase"><span class="tocnumber">1.4</span> <span class="toctext">Chrysoprase</span></a></li>
<li class="toclevel-2 tocsection-6"><a href="#Heliotrope"><span class="tocnumber">1.5</span> <span class="toctext">Heliotrope</span></a></li>
<li class="toclevel-2 tocsection-7"><a href="#Moss_agate"><span class="tocnumber">1.6</span> <span class="toctext">Moss agate</span></a></li>
<li class="toclevel-2 tocsection-8"><a href="#Mtorolite"><span class="tocnumber">1.7</span> <span class="toctext">Mtorolite</span></a></li>
<li class="toclevel-2 tocsection-9"><a href="#Onyx"><span class="tocnumber">1.8</span> <span class="toctext">Onyx</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-10"><a href="#History"><span class="tocnumber">2</span> <span class="toctext">History</span></a></li>
<li class="toclevel-1 tocsection-11"><a href="#Geochemistry"><span class="tocnumber">3</span> <span class="toctext">Geochemistry</span></a>
<ul>
<li class="toclevel-2 tocsection-12"><a href="#Structure"><span class="tocnumber">3.1</span> <span class="toctext">Structure</span></a></li>
<li class="toclevel-2 tocsection-13"><a href="#Solubility"><span class="tocnumber">3.2</span> <span class="toctext">Solubility</span></a>
<ul>
<li class="toclevel-3 tocsection-14"><a href="#Solubility_of_quartz_and_chalcedony_in_pure_water"><span class="tocnumber">3.2.1</span> <span class="toctext">Solubility of quartz and chalcedony in pure water</span></a></li>
</ul>
</li>
</ul>
</li>
<li class="toclevel-1 tocsection-15"><a href="#See_also"><span class="tocnumber">4</span> <span class="toctext">See also</span></a></li>
<li class="toclevel-1 tocsection-16"><a href="#References"><span class="tocnumber">5</span> <span class="toctext">References</span></a></li>
<li class="toclevel-1 tocsection-17"><a href="#External_links"><span class="tocnumber">6</span> <span class="toctext">External links</span></a></li>
</ul>
</div>
<h2><span class="mw-headline" id="Varieties">Varieties</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=1" title="Edit section: Varieties">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<p>Chalcedony occurs in a wide range of varieties. Many semi-precious <a href="/enwiki/wiki/Gemstone" title="Gemstone">gemstones</a> are in fact forms of chalcedony. The more notable varieties of chalcedony are as follows:
</p>
<h3><span class="mw-headline" id="Agate">Agate</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=2" title="Edit section: Agate">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<div class="thumb tleft"><div class="thumbinner" style="width:182px;"><a href="/enwiki/wiki/File:Quartz_-_Agateplate,_redbrown-white.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/b/ba/Quartz_-_Agateplate%2C_redbrown-white.jpg/180px-Quartz_-_Agateplate%2C_redbrown-white.jpg" decoding="async" width="180" height="109" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/b/ba/Quartz_-_Agateplate%2C_redbrown-white.jpg/270px-Quartz_-_Agateplate%2C_redbrown-white.jpg 1.5x, /upwiki/wikipedia/commons/thumb/b/ba/Quartz_-_Agateplate%2C_redbrown-white.jpg/360px-Quartz_-_Agateplate%2C_redbrown-white.jpg 2x" data-file-width="2800" data-file-height="1700" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Quartz_-_Agateplate,_redbrown-white.jpg" class="internal" title="Enlarge"></a></div>Agate</div></div></div>
<p><b><a href="/enwiki/wiki/Agate" title="Agate">Agate</a></b> is a variety of chalcedony characterized by either transparency or color patterns, such as multi-colored curved or angular banding. Opaque varieties are sometimes referred to as <a href="/enwiki/wiki/Jasper" title="Jasper">jasper</a>.<sup id="cite_ref-gemsociety_3-1" class="reference"><a href="#cite_note-gemsociety-3">[3]</a></sup> Fire agate shows iridescent phenomena on a brown background; iris agate shows exceptional <a href="/enwiki/wiki/Iridescence" title="Iridescence">iridescence</a> when light (especially pinpointed light) is shone through the stone. Landscape agate is chalcedony with a number of different mineral impurities making the stone resemble landscapes.<sup id="cite_ref-cibjo_7-0" class="reference"><a href="#cite_note-cibjo-7">[7]</a></sup>
</p>
<div style="clear:both;"></div>
<h3><span class="mw-headline" id="Aventurine">Aventurine</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=3" title="Edit section: Aventurine">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<div class="thumb tleft"><div class="thumbinner" style="width:182px;"><a href="/enwiki/wiki/File:Aventurine.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/8/84/Aventurine.jpg/180px-Aventurine.jpg" decoding="async" width="180" height="135" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/8/84/Aventurine.jpg/270px-Aventurine.jpg 1.5x, /upwiki/wikipedia/commons/thumb/8/84/Aventurine.jpg/360px-Aventurine.jpg 2x" data-file-width="800" data-file-height="600" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Aventurine.jpg" class="internal" title="Enlarge"></a></div>Aventurine (<i>Unknown scale</i>)</div></div></div>
<p><b><a href="/enwiki/wiki/Aventurine" title="Aventurine">Aventurine</a></b> is a form of quartz, characterised by its translucency and the presence of platy <a href="/enwiki/wiki/Mineral" title="Mineral">mineral</a> <a href="/enwiki/wiki/Inclusion_(mineral)" title="Inclusion (mineral)">inclusions</a> that give a shimmering or glistening effect termed <a href="/enwiki/wiki/Aventurescence" title="Aventurescence">aventurescence</a>. Chrome-bearing <a href="/enwiki/wiki/Fuchsite" title="Fuchsite">fuchsite</a> (a variety of <a href="/enwiki/wiki/Muscovite" title="Muscovite">muscovite</a> <a href="/enwiki/wiki/Mica" title="Mica">mica</a>) is the classic inclusion, and gives a silvery green or blue sheen. Oranges and browns are attributed to <a href="/enwiki/wiki/Hematite" title="Hematite">hematite</a> or <a href="/enwiki/wiki/Goethite" title="Goethite">goethite</a>.
</p>
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<h3><span class="mw-headline" id="Carnelian">Carnelian</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=4" title="Edit section: Carnelian">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<div class="thumb tleft"><div class="thumbinner" style="width:182px;"><a href="/enwiki/wiki/File:Carnelian_sard_(mineral_specimen).jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/1/12/Carnelian_sard_%28mineral_specimen%29.jpg/180px-Carnelian_sard_%28mineral_specimen%29.jpg" decoding="async" width="180" height="108" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/1/12/Carnelian_sard_%28mineral_specimen%29.jpg/270px-Carnelian_sard_%28mineral_specimen%29.jpg 1.5x, /upwiki/wikipedia/commons/thumb/1/12/Carnelian_sard_%28mineral_specimen%29.jpg/360px-Carnelian_sard_%28mineral_specimen%29.jpg 2x" data-file-width="1250" data-file-height="750" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Carnelian_sard_(mineral_specimen).jpg" class="internal" title="Enlarge"></a></div>Carnelian</div></div></div>
<p><b><a href="/enwiki/wiki/Carnelian" title="Carnelian">Carnelian</a></b> (also spelled cornelian) is a clear-to-translucent reddish-brown variety of chalcedony. Its hue may vary from a pale orange, to an intense almost-black coloration. Similar to carnelian is <a href="/enwiki/wiki/Carnelian" title="Carnelian">sard</a>, which is brown rather than red.
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<h3><span class="mw-headline" id="Chrysoprase">Chrysoprase</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=5" title="Edit section: Chrysoprase">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<div class="thumb tleft"><div class="thumbinner" style="width:182px;"><a href="/enwiki/wiki/File:Chryzopras_Polsko.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/d/d0/Chryzopras_Polsko.jpg/180px-Chryzopras_Polsko.jpg" decoding="async" width="180" height="120" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/d/d0/Chryzopras_Polsko.jpg/270px-Chryzopras_Polsko.jpg 1.5x, /upwiki/wikipedia/commons/thumb/d/d0/Chryzopras_Polsko.jpg/360px-Chryzopras_Polsko.jpg 2x" data-file-width="960" data-file-height="640" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Chryzopras_Polsko.jpg" class="internal" title="Enlarge"></a></div>Chrysoprase</div></div></div>
<p><b><a href="/enwiki/wiki/Chrysoprase" title="Chrysoprase">Chrysoprase</a></b> (also spelled chrysophrase) is a green variety of chalcedony, which has been colored by <a href="/enwiki/wiki/Nickel(II)_oxide" title="Nickel(II) oxide">nickel oxide</a>. (The darker varieties of chrysoprase are also referred to as prase. However, the term prase is also used to describe green <a href="/enwiki/wiki/Quartz" title="Quartz">quartz</a>, and to a certain extent is a color-descriptor, rather than a rigorously defined mineral variety.)
</p><p>Blue-colored chalcedony is sometimes referred to as "blue chrysoprase" if the color is sufficiently rich, though it derives its color from the presence of <a href="/enwiki/wiki/Copper" title="Copper">copper</a> and is largely unrelated to nickel-bearing chrysoprase.
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<h3><span class="mw-headline" id="Heliotrope">Heliotrope</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=6" title="Edit section: Heliotrope">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<div class="thumb tleft"><div class="thumbinner" style="width:182px;"><a href="/enwiki/wiki/File:Quarz_-_Heliotrop_(Blutjaspis).JPG" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/8/87/Quarz_-_Heliotrop_%28Blutjaspis%29.JPG/180px-Quarz_-_Heliotrop_%28Blutjaspis%29.JPG" decoding="async" width="180" height="156" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/8/87/Quarz_-_Heliotrop_%28Blutjaspis%29.JPG/270px-Quarz_-_Heliotrop_%28Blutjaspis%29.JPG 1.5x, /upwiki/wikipedia/commons/thumb/8/87/Quarz_-_Heliotrop_%28Blutjaspis%29.JPG/360px-Quarz_-_Heliotrop_%28Blutjaspis%29.JPG 2x" data-file-width="1630" data-file-height="1413" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Quarz_-_Heliotrop_(Blutjaspis).JPG" class="internal" title="Enlarge"></a></div>Heliotrope, or bloodstone</div></div></div>
<p><b><a href="/enwiki/wiki/Heliotrope_(mineral)" title="Heliotrope (mineral)">Heliotrope</a></b> is a green variety of chalcedony, containing red inclusions of <a href="/enwiki/wiki/Iron_oxide" title="Iron oxide">iron oxide</a> that resemble drops of <a href="/enwiki/wiki/Blood" title="Blood">blood</a>, giving heliotrope its alternative name of bloodstone. In a similar variety, the spots are yellow instead, known as plasma.
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<h3><span class="mw-headline" id="Moss_agate">Moss agate</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=7" title="Edit section: Moss agate">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<div class="thumb tleft"><div class="thumbinner" style="width:182px;"><a href="/enwiki//en.wikipedia.org/wiki/Special:Upload?wpDestFile=Mossagate.pebble.750piax.jpg" class="new" title="File:Mossagate.pebble.750piax.jpg">File:Mossagate.pebble.750piax.jpg</a> <div class="thumbcaption">Tree agate</div></div></div>
<p><b><a href="/enwiki/wiki/Moss_agate" title="Moss agate">Moss agate</a></b> contains green filament-like inclusions, giving it the superficial appearance of <a href="/enwiki/wiki/Moss" title="Moss">moss</a> or <a href="/enwiki/wiki/Blue_cheese" title="Blue cheese">blue cheese</a>. There is also tree agate which is similar to moss agate except it is solid white with green filaments whereas moss agate usually has a transparent background, so the "moss" appears in 3D. It is not a true form of agate, as it lacks agate's defining feature of concentric banding.
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<h3><span class="mw-headline" id="Mtorolite">Mtorolite</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=8" title="Edit section: Mtorolite">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<div class="thumb tleft"><div class="thumbinner" style="width:182px;"><a href="/enwiki/wiki/File:Mtorolite_zimbabwe_trimmed.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/9/9f/Mtorolite_zimbabwe_trimmed.jpg/180px-Mtorolite_zimbabwe_trimmed.jpg" decoding="async" width="180" height="113" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/9/9f/Mtorolite_zimbabwe_trimmed.jpg/270px-Mtorolite_zimbabwe_trimmed.jpg 1.5x, /upwiki/wikipedia/commons/thumb/9/9f/Mtorolite_zimbabwe_trimmed.jpg/360px-Mtorolite_zimbabwe_trimmed.jpg 2x" data-file-width="2538" data-file-height="1593" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Mtorolite_zimbabwe_trimmed.jpg" class="internal" title="Enlarge"></a></div>Mtorolite</div></div></div>
<p><b><a href="/enwiki/wiki/Mtorolite" class="mw-redirect" title="Mtorolite">Mtorolite</a></b> is a green variety of chalcedony, which has been colored by <a href="/enwiki/wiki/Chromium" title="Chromium">chromium</a>. Also known as <a href="/enwiki/wiki/Chrome_chalcedony" title="Chrome chalcedony">chrome chalcedony</a>, it is principally found in <a href="/enwiki/wiki/Zimbabwe" title="Zimbabwe">Zimbabwe</a>.
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<h3><span class="mw-headline" id="Onyx">Onyx</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=9" title="Edit section: Onyx">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<div class="thumb tleft"><div class="thumbinner" style="width:182px;"><a href="/enwiki/wiki/File:Agate-Quartz-49959.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/b/b3/Agate-Quartz-49959.jpg/180px-Agate-Quartz-49959.jpg" decoding="async" width="180" height="169" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/b/b3/Agate-Quartz-49959.jpg/270px-Agate-Quartz-49959.jpg 1.5x, /upwiki/wikipedia/commons/thumb/b/b3/Agate-Quartz-49959.jpg/360px-Agate-Quartz-49959.jpg 2x" data-file-width="600" data-file-height="564" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Agate-Quartz-49959.jpg" class="internal" title="Enlarge"></a></div>Onyx</div></div></div>
<p><b><a href="/enwiki/wiki/Onyx" title="Onyx">Onyx</a></b> is a variant of agate with black and white banding. Similarly, agate with brown, orange, red and white banding is known as <a href="/enwiki/wiki/Sardonyx" class="mw-redirect" title="Sardonyx">sardonyx</a>.
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<h2><span class="mw-headline" id="History">History</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=10" title="Edit section: History">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/enwiki/wiki/File:Titus_cameo.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/7/79/Titus_cameo.jpg/220px-Titus_cameo.jpg" decoding="async" width="220" height="280" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/7/79/Titus_cameo.jpg/330px-Titus_cameo.jpg 1.5x, /upwiki/wikipedia/commons/thumb/7/79/Titus_cameo.jpg/440px-Titus_cameo.jpg 2x" data-file-width="513" data-file-height="654" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Titus_cameo.jpg" class="internal" title="Enlarge"></a></div>Chalcedony <a href="/enwiki/wiki/Cameo_(carving)" title="Cameo (carving)">cameo</a> of <a href="/enwiki/wiki/Titus" title="Titus">Titus</a> head, 2nd Century AD</div></div></div>
<p>As early as the <a href="/enwiki/wiki/Bronze_Age" title="Bronze Age">Bronze Age</a> chalcedony was in use in the <a href="/enwiki/wiki/Mediterranean" class="mw-redirect" title="Mediterranean">Mediterranean</a> region; for example, on <a href="/enwiki/wiki/Minoan_civilization" title="Minoan civilization">Minoan</a> <a href="/enwiki/wiki/Crete" title="Crete">Crete</a> at the Palace of <a href="/enwiki/wiki/Knossos" title="Knossos">Knossos</a>, chalcedony <a href="/enwiki/wiki/Minoan_seal-stones" class="mw-redirect" title="Minoan seal-stones">seals</a> have been recovered dating to circa 1800 <a href="/enwiki/wiki/Before_Christ" class="mw-redirect" title="Before Christ">BC</a>.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8">[8]</a></sup> People living along the <a href="/enwiki/wiki/Central_Asia" title="Central Asia">Central Asian</a> trade routes used various forms of chalcedony, including <a href="/enwiki/wiki/Carnelian" title="Carnelian">carnelian</a>, to carve <a href="/enwiki/wiki/Intaglio_(jewellery)" class="mw-redirect" title="Intaglio (jewellery)">intaglios</a>, ring bezels (the upper faceted portion of a gem projecting from the ring setting), and beads that show strong Greco-Roman influence.
</p><p>Fine examples of first century objects made from chalcedony, possibly <a href="/enwiki/wiki/Kushan" class="mw-redirect" title="Kushan">Kushan</a>, were found in recent years at <a href="/enwiki/wiki/Tillya-tepe" class="mw-redirect" title="Tillya-tepe">Tillya-tepe</a> in north-western <a href="/enwiki/wiki/Afghanistan" title="Afghanistan">Afghanistan</a>.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9">[9]</a></sup> Hot wax would not stick to it so it was often used to make <a href="/enwiki/wiki/Seal_(device)" class="mw-redirect" title="Seal (device)">seal</a> impressions.
The term <i>chalcedony</i> is derived from the name of the ancient Greek town Chalkedon in <a href="/enwiki/wiki/Asia_Minor" class="mw-redirect" title="Asia Minor">Asia Minor</a>, in modern English usually spelled <a href="/enwiki/wiki/Chalcedon" title="Chalcedon">Chalcedon</a>, today the <a href="/enwiki/wiki/Kad%C4%B1k%C3%B6y" title="Kadıköy">Kadıköy</a> district of <a href="/enwiki/wiki/Istanbul" title="Istanbul">Istanbul</a>.
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<div class="thumb tleft"><div class="thumbinner" style="width:302px;"><a href="/enwiki/wiki/File:ChalcedonyKnifeNPS.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/5/58/ChalcedonyKnifeNPS.jpg/300px-ChalcedonyKnifeNPS.jpg" decoding="async" width="300" height="112" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/5/58/ChalcedonyKnifeNPS.jpg/450px-ChalcedonyKnifeNPS.jpg 1.5x, /upwiki/wikipedia/commons/thumb/5/58/ChalcedonyKnifeNPS.jpg/600px-ChalcedonyKnifeNPS.jpg 2x" data-file-width="650" data-file-height="243" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:ChalcedonyKnifeNPS.jpg" class="internal" title="Enlarge"></a></div>Chalcedony knife, AD 1000-1200</div></div></div>
<p>According to tradition, at least three varieties of chalcedony were used in the Jewish High Priest's Breastplate. (Jewish tradition states that Moses' brother Aaron wore the Breastplate, with inscribed gems representing the twelve tribes of Israel). The Breastplate supposedly included <i>jasper</i>, <i>chrysoprase</i> and <i>sardonyx</i>, and there is some debate as to whether other <i>agates</i> were also used.
</p><p>In the 19th century, <a href="/enwiki/wiki/Idar-Oberstein" title="Idar-Oberstein">Idar-Oberstein</a>, Germany, became the world's largest chalcedony processing center, working mostly on agates. Most of these agates were from Latin America, in particular Brazil. Originally the agate carving industry around Idar and Oberstein was driven by local deposits that were mined in the 15th century.<sup id="cite_ref-streeter1_10-0" class="reference"><a href="#cite_note-streeter1-10">[10]</a></sup> Several factors contributed to the re-emergence of Idar-Oberstein as agate center of the world: ships brought agate nodules back as ballast, thus providing extremely cheap transport. In addition, cheap labor and a superior knowledge of chemistry allowed them to dye the agates in any color with processes that were kept secret. Each mill in Idar-Oberstein had four or five grindstones. These were of red sandstone, obtained from Zweibrücken; and two men ordinarily worked together at the same stone.<sup id="cite_ref-streeter1_10-1" class="reference"><a href="#cite_note-streeter1-10">[10]</a></sup>
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<h2><span class="mw-headline" id="Geochemistry">Geochemistry</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=11" title="Edit section: Geochemistry">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/enwiki/wiki/File:Sumin_chalcedony_mouse.jpg" class="image"><img alt="" src="/upwiki/wikipedia/commons/thumb/c/c1/Sumin_chalcedony_mouse.jpg/220px-Sumin_chalcedony_mouse.jpg" decoding="async" width="220" height="147" class="thumbimage" srcset="/upwiki/wikipedia/commons/thumb/c/c1/Sumin_chalcedony_mouse.jpg/330px-Sumin_chalcedony_mouse.jpg 1.5x, /upwiki/wikipedia/commons/thumb/c/c1/Sumin_chalcedony_mouse.jpg/440px-Sumin_chalcedony_mouse.jpg 2x" data-file-width="3392" data-file-height="2261" /></a> <div class="thumbcaption"><div class="magnify"><a href="/enwiki/wiki/File:Sumin_chalcedony_mouse.jpg" class="internal" title="Enlarge"></a></div>chalcedony mouse, by <a href="/enwiki/wiki/Avenir_Sumin" title="Avenir Sumin">Avenir Sumin</a></div></div></div>
<h3><span class="mw-headline" id="Structure">Structure</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=12" title="Edit section: Structure">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<p>Chalcedony was once thought to be a fibrous variety of cryptocrystalline <a href="/enwiki/wiki/Quartz" title="Quartz">quartz</a>.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11">[11]</a></sup> More recently however, it has been shown to also contain a <a href="/enwiki/wiki/Monoclinic" class="mw-redirect" title="Monoclinic">monoclinic</a> polymorph of quartz, known as <a href="/enwiki/wiki/Moganite" title="Moganite">moganite</a>.<sup id="cite_ref-heany_1994_2-1" class="reference"><a href="#cite_note-heany_1994-2">[2]</a></sup> The fraction, by mass, of moganite within a typical chalcedony sample may vary from less than 5% to over 20%.<sup id="cite_ref-heany_1992_12-0" class="reference"><a href="#cite_note-heany_1992-12">[12]</a></sup> The existence of moganite was once regarded as dubious, but it is now officially recognised by the <a href="/enwiki/wiki/International_Mineralogical_Association" title="International Mineralogical Association">International Mineralogical Association</a>.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13">[13]</a></sup><sup id="cite_ref-14" class="reference"><a href="#cite_note-14">[14]</a></sup>
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<h3><span class="mw-headline" id="Solubility">Solubility</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=13" title="Edit section: Solubility">edit</a><span class="mw-editsection-bracket">]</span></span></h3>
<p>Chalcedony is more <a href="/enwiki/wiki/Soluble" class="mw-redirect" title="Soluble">soluble</a> than quartz under low-temperature conditions, despite the two minerals being chemically identical. This is thought to be because chalcedony is extremely finely grained (cryptocrystalline), and so has a very high surface area to volume ratio.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/enwiki/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (February 2007)">citation needed</span></a></i>]</sup> It has also been suggested that the higher solubility is due to the moganite component.<sup id="cite_ref-heany_1992_12-1" class="reference"><a href="#cite_note-heany_1992-12">[12]</a></sup>
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<h4><span class="mw-headline" id="Solubility_of_quartz_and_chalcedony_in_pure_water">Solubility of quartz and chalcedony in pure water</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=14" title="Edit section: Solubility of quartz and chalcedony in pure water">edit</a><span class="mw-editsection-bracket">]</span></span></h4>
<p>This table gives equilibrium concentrations of total dissolved silicon as calculated by <i>PHREEQC</i> (PH REdox EQuilibrium (in C language, USGS)) using the llnl.dat database.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/enwiki/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (December 2009)">citation needed</span></a></i>]</sup>
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<table class="wikitable" style="margin:auto">
<tbody><tr>
<th>Temperature
</th>
<th>Quartz solubility (mg/L)
</th>
<th>Chalcedony solubility (mg/L)
</th></tr>
<tr>
<th>0.01 °C
</th>
<td>0.68
</td>
<td>1.34
</td></tr>
<tr>
<th>25.0 °C
</th>
<td>2.64
</td>
<td>4.92
</td></tr>
<tr>
<th>50.0 °C
</th>
<td>6.95
</td>
<td>12.35
</td></tr>
<tr>
<th>75.0 °C
</th>
<td>14.21
</td>
<td>24.23
</td></tr>
<tr>
<th>100.0 °C
</th>
<td>24.59
</td>
<td>40.44
</td></tr></tbody></table>
<h2><span class="mw-headline" id="See_also">See also</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=15" title="Edit section: See also">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<ul><li><a href="/enwiki/wiki/List_of_minerals" title="List of minerals">List of minerals</a></li></ul>
<h2><span class="mw-headline" id="References">References</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=16" title="Edit section: References">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<div class="reflist" style="list-style-type: decimal;">
<div class="mw-references-wrap mw-references-columns"><ol class="references">
<li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><cite class="citation book">Duda, Rudolf; Rejl, Lubos (1990). <i>Minerals of the World</i>. Arch Cape Press.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Minerals+of+the+World&rft.pub=Arch+Cape+Press&rft.date=1990&rft.aulast=Duda&rft.aufirst=Rudolf&rft.au=Rejl%2C+Lubos&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><style data-mw-deduplicate="TemplateStyles:r886058088">.mw-parser-output cite.citation{font-style:inherit}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation .cs1-lock-free a{background:url("/upwiki/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration a{background:url("/upwiki/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-subscription a{background:url("/upwiki/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-ws-icon a{background:url("/upwiki/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-maint{display:none;color:#33aa33;margin-left:0.3em}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}</style></span>
</li>
<li id="cite_note-heany_1994-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-heany_1994_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-heany_1994_2-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite class="citation book">Heaney, Peter J. (1994). "Structure and Chemistry of the low-pressure silica polymorphs". In Heaney, P. J.; Prewitt, C. T.; Gibbs, G. V. <i>Silica: Physical Behavior, geochemistry and materials applications</i>. Reviews in Mineralogy. <b>29</b>. pp. 1–40.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Structure+and+Chemistry+of+the+low-pressure+silica+polymorphs&rft.btitle=Silica%3A+Physical+Behavior%2C+geochemistry+and+materials+applications&rft.series=Reviews+in+Mineralogy&rft.pages=1-40&rft.date=1994&rft.aulast=Heaney&rft.aufirst=Peter+J.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-gemsociety-3"><span class="mw-cite-backlink">^ <a href="#cite_ref-gemsociety_3-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-gemsociety_3-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite class="citation web"><a rel="nofollow" class="external text" href="http://www.gemsociety.org/article/chalcedony-jewelry-and-gemstone-information/">"Chalcedony Gemological Information"</a>. International Gem Society (IGS). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20150207162538/http://www.gemsociety.org/article/chalcedony-jewelry-and-gemstone-information/">Archived</a> from the original on 7 February 2015<span class="reference-accessdate">. Retrieved <span class="nowrap">16 January</span> 2015</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Chalcedony+Gemological+Information&rft.pub=International+Gem+Society+%28IGS%29&rft_id=http%3A%2F%2Fwww.gemsociety.org%2Farticle%2Fchalcedony-jewelry-and-gemstone-information%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"><cite class="citation book">Pliny the Elder. <a rel="nofollow" class="external text" href="https://books.google.com/books?id=oHlGAAAAYAAJ&pg=PA163">"chapter 7"</a>. <i><a href="/enwiki/wiki/Natural_History_(Pliny)" title="Natural History (Pliny)">Naturalis Historiae</a></i>. Book 37. p. 115.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=chapter+7&rft.btitle=Naturalis+Historiae&rft.pages=115&rft.au=Pliny+the+Elder&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DoHlGAAAAYAAJ%26pg%3DPA163&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"><cite class="citation book">Zwierlein-Diehl, Erika (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=OtaMtKzaKR8C&pg=PA307"><i>Antike Gemmen und ihr Nachleben</i></a>. Berlin: Verlag <a href="/enwiki/wiki/Walter_de_Gruyter" title="Walter de Gruyter">Walter de Gruyter</a>. S. 307.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Antike+Gemmen+und+ihr+Nachleben&rft.place=Berlin&rft.pages=S.+307&rft.pub=Verlag+Walter+de+Gruyter&rft.date=2007&rft.aulast=Zwierlein-Diehl&rft.aufirst=Erika&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DOtaMtKzaKR8C%26pg%3DPA307&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/> According to the <a href="/enwiki/wiki/OED" class="mw-redirect" title="OED">OED</a> a connection with the town of Chalcedon is "very doubtful":<cite class="citation web">Harper, Douglas. <a rel="nofollow" class="external text" href="http://www.etymonline.com/?term=Chalcedony">"Chalcedony"</a>. <i><a href="/enwiki/wiki/Online_Etymology_Dictionary" title="Online Etymology Dictionary">Online Etymology Dictionary</a></i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Online+Etymology+Dictionary&rft.atitle=Chalcedony&rft.aulast=Harper&rft.aufirst=Douglas&rft_id=http%3A%2F%2Fwww.etymonline.com%2F%3Fterm%3DChalcedony&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><cite class="citation book">James Orr, ed. (1915). "<i>Chalkēdōn</i>". <a rel="nofollow" class="external text" href="https://books.google.com/?id=CqPNAAAAMAAJ&pg=PA2859&dq=chalcedony+Chalkedon#v=onepage&q=chalcedony%20Chalkedon&f=false"><i>The International Standard Bible Encyclopaedia</i></a>. The Howard-Severance company. p. 2859.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Chalk%C4%93d%C5%8Dn&rft.btitle=The+International+Standard+Bible+Encyclopaedia&rft.pages=2859&rft.pub=The+Howard-Severance+company&rft.date=1915&rft_id=https%3A%2F%2Fbooks.google.com%2F%3Fid%3DCqPNAAAAMAAJ%26pg%3DPA2859%26dq%3Dchalcedony%2BChalkedon%23v%3Donepage%26q%3Dchalcedony%2520Chalkedon%26f%3Dfalse&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-cibjo-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-cibjo_7-0">^</a></b></span> <span class="reference-text"><cite class="citation web">CIBJO member laboratories (May 2009). <a rel="nofollow" class="external text" href="http://www.cibjo.org/index.php?option=com_content&view=article&id=55&Itemid=32">"Retailers' Reference Guide: Diamonds, Cemstones, Pearls and Precious Metals"</a>. Bern, Switzerland: CIBJO (The World Jewellery Federation, international federation of all national trade organizations and gemological laboratories).</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Retailers%27+Reference+Guide%3A+Diamonds%2C+Cemstones%2C+Pearls+and+Precious+Metals&rft.place=Bern%2C+Switzerland&rft.pub=CIBJO+%28The+World+Jewellery+Federation%2C+international+federation+of+all+national+trade+organizations+and+gemological+laboratories%29&rft.date=2009-05&rft.au=CIBJO+member+laboratories&rft_id=http%3A%2F%2Fwww.cibjo.org%2Findex.php%3Foption%3Dcom_content%26view%3Darticle%26id%3D55%26Itemid%3D32&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><cite class="citation web">Hogan, C. Michael (2007). <a rel="nofollow" class="external text" href="http://www.themodernantiquarian.com/site/10854/knossos.html#fieldnotes">"Knossos fieldnotes"</a>. Modern Antiquarian. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160409225800/http://www.themodernantiquarian.com/site/10854/knossos.html#fieldnotes">Archived</a> from the original on 2016-04-09.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Knossos+fieldnotes&rft.pub=Modern+Antiquarian&rft.date=2007&rft.aulast=Hogan&rft.aufirst=C.+Michael&rft_id=http%3A%2F%2Fwww.themodernantiquarian.com%2Fsite%2F10854%2Fknossos.html%23fieldnotes&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text">Section 12 of the translation of <i>Weilue</i> - a 3rd-century Chinese text by John Hill under "carnelian" and note 12.12 (17)A. Also see Afghanistan's exhibition:<a rel="nofollow" class="external text" href="http://www.farlang.com/profiles/afghanistan-museum-kabul/product.2009-03-24.6644617360">Intaglio with depiction of a griffin, Chalcedony, 4th century BC, Afghanistan</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20120225063934/http://www.farlang.com/profiles/afghanistan-museum-kabul/product.2009-03-24.6644617360">Archived</a> February 25, 2012, at the <a href="/enwiki/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a></span>
</li>
<li id="cite_note-streeter1-10"><span class="mw-cite-backlink">^ <a href="#cite_ref-streeter1_10-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-streeter1_10-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite class="citation book">Streeter, Edwin (1898). <i>Precious Stones and Gems</i>. p. 237.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Precious+Stones+and+Gems&rft.pages=237&rft.date=1898&rft.aulast=Streeter&rft.aufirst=Edwin&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><cite class="citation web"><a rel="nofollow" class="external text" href="http://www.mindat.org/min-960.html">"Chalcedony mineral information and data"</a>. <i>www.mindat.org</i>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060821000434/http://www.mindat.org/min-960.html">Archived</a> from the original on 2006-08-21.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.mindat.org&rft.atitle=Chalcedony+mineral+information+and+data&rft_id=http%3A%2F%2Fwww.mindat.org%2Fmin-960.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-heany_1992-12"><span class="mw-cite-backlink">^ <a href="#cite_ref-heany_1992_12-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-heany_1992_12-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite class="citation journal">Heaney, Peter J.; Post, Jeffrey E. (24 January 1992). "The Widespread Distribution of a Novel Silica Polymorph in Microcrystalline Quartz Varieties". <i>Science</i>. New Series. <b>255</b> (5043): 441–443. <a href="/enwiki/wiki/Digital_object_identifier" title="Digital object identifier">doi</a>:<a rel="nofollow" class="external text" href="/enwiki//doi.org/10.1126%2Fscience.255.5043.4">10.1126/science.255.5043.4</a>. <a href="/enwiki/wiki/JSTOR" title="JSTOR">JSTOR</a> <a rel="nofollow" class="external text" href="/enwiki//www.jstor.org/stable/2876012">2876012</a>. <a href="/enwiki/wiki/PubMed_Identifier" class="mw-redirect" title="PubMed Identifier">PMID</a> <a rel="nofollow" class="external text" href="/enwiki//www.ncbi.nlm.nih.gov/pubmed/17842895">17842895</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Science&rft.atitle=The+Widespread+Distribution+of+a+Novel+Silica+Polymorph+in+Microcrystalline+Quartz+Varieties&rft.volume=255&rft.issue=5043&rft.pages=441-443&rft.date=1992-01-24&rft_id=info%3Apmid%2F17842895&rft_id=%2F%2Fwww.jstor.org%2Fstable%2F2876012&rft_id=info%3Adoi%2F10.1126%2Fscience.255.5043.4&rft.aulast=Heaney&rft.aufirst=Peter+J.&rft.au=Post%2C+Jeffrey+E.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><cite class="citation journal">Origlieri, Marcus (January 1994). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20080309094336/http://fgms.home.att.net/moganite.htm">"Moganite: a New Mineral -- Not!"</a>. <i>Lithosphere</i>. Archived from <a rel="nofollow" class="external text" href="http://fgms.home.att.net/moganite.htm">the original</a> on March 9, 2008.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Lithosphere&rft.atitle=Moganite%3A+a+New+Mineral+--+Not%21&rft.date=1994-01&rft.aulast=Origlieri&rft.aufirst=Marcus&rft_id=http%3A%2F%2Ffgms.home.att.net%2Fmoganite.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/></span>
</li>
<li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><cite class="citation journal">Nickel, Ernest H.; Nichols, Monte C. (16 May 2008). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20080530134400/http://www.geo.vu.nl/users/ima-cnmmn/MINERALlist.pdf">"IMA/CNMNC List of Mineral Names"</a> <span class="cs1-format">(PDF)</span>. <i>Materials Data</i>. Archived from <a rel="nofollow" class="external text" href="http://www.geo.vu.nl/users/ima-cnmmn/MINERALlist.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2008-05-30<span class="reference-accessdate">. Retrieved <span class="nowrap">2008-06-29</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Materials+Data&rft.atitle=IMA%2FCNMNC+List+of+Mineral+Names&rft.date=2008-05-16&rft.aulast=Nickel&rft.aufirst=Ernest+H.&rft.au=Nichols%2C+Monte+C.&rft_id=http%3A%2F%2Fwww.geo.vu.nl%2Fusers%2Fima-cnmmn%2FMINERALlist.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChalcedony" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r886058088"/>></span>
</li>
</ol></div></div>
<h2><span class="mw-headline" id="External_links">External links</span><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/enwiki/w/index.php?title=Chalcedony&action=edit&section=17" title="Edit section: External links">edit</a><span class="mw-editsection-bracket">]</span></span></h2>
<table role="presentation" class="mbox-small plainlinks sistersitebox" style="background-color:#f9f9f9;border:1px solid #aaa;color:#000">
<tbody><tr>
<td class="mbox-image"><img alt="" src="/upwiki/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/38px-Wikisource-logo.svg.png" decoding="async" width="38" height="40" class="noviewer" srcset="/upwiki/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/57px-Wikisource-logo.svg.png 1.5x, /upwiki/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/76px-Wikisource-logo.svg.png 2x" data-file-width="410" data-file-height="430" /></td>
<td class="mbox-text plainlist"><a href="/enwiki/wiki/Wikisource" title="Wikisource">Wikisource</a> has the text of the <a href="/enwiki/wiki/Encyclop%C3%A6dia_Britannica_Eleventh_Edition" title="Encyclopædia Britannica Eleventh Edition">1911 <i>Encyclopædia Britannica</i></a> article <i><b><a href="https://en.wikisource.org/wiki/1911_Encyclop%C3%A6dia_Britannica/Chalcedony" class="extiw" title="wikisource:1911 Encyclopædia Britannica/Chalcedony">Chalcedony</a></b></i>.</td></tr></tbody></table>
<ul><li><a href="/enwiki/wiki/File:Commons-logo.svg" class="image"><img alt="" src="/upwiki/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png" decoding="async" width="12" height="16" class="noviewer" srcset="/upwiki/wikipedia/en/thumb/4/4a/Commons-logo.svg/18px-Commons-logo.svg.png 1.5x, /upwiki/wikipedia/en/thumb/4/4a/Commons-logo.svg/24px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></a> Media related to <a href="https://commons.wikimedia.org/wiki/Category:Chalcedony" class="extiw" title="commons:Category:Chalcedony">Chalcedony</a> at Wikimedia Commons</li>
<li><a rel="nofollow" class="external text" href="http://www.mindat.org/min-960.html">Mindat: mineralogical data Chalcedony</a></li>
<li><a rel="nofollow" class="external text" href="http://minerals.usgs.gov/minerals/pubs/commodity/gemstones/sp14-95/chalcedony.html">USGS: US Chalcedony locations</a></li></ul>
<div role="navigation" class="navbox" aria-labelledby="Silica_minerals" style="padding:3px"><table class="nowraplinks collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div class="plainlinks hlist navbar mini"><ul><li class="nv-view"><a href="/enwiki/wiki/Template:Silica_minerals" title="Template:Silica minerals"><abbr title="View this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">v</abbr></a></li><li class="nv-talk"><a href="/enwiki/wiki/Template_talk:Silica_minerals" title="Template talk:Silica minerals"><abbr title="Discuss this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">t</abbr></a></li><li class="nv-edit"><a class="external text" href="/enwiki//en.wikipedia.org/enwiki/w/index.php?title=Template:Silica_minerals&action=edit"><abbr title="Edit this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">e</abbr></a></li></ul></div><div id="Silica_minerals" style="font-size:114%;margin:0 4em"><a href="/enwiki/wiki/Silicon_dioxide" title="Silicon dioxide">Silica</a> <a href="/enwiki/wiki/Mineral" title="Mineral">minerals</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Crystal_structure" title="Crystal structure">Crystalline</a></th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Coesite" title="Coesite">Coesite</a></li>
<li><a href="/enwiki/wiki/Cristobalite" title="Cristobalite">Cristobalite</a></li>
<li><a href="/enwiki/wiki/Keatite" title="Keatite">Keatite</a></li>
<li><a href="/enwiki/wiki/Moganite" title="Moganite">Moganite</a></li>
<li><a href="/enwiki/wiki/Quartz" title="Quartz">Quartz</a></li>
<li><a href="/enwiki/wiki/Seifertite" title="Seifertite">Seifertite</a></li>
<li><a href="/enwiki/wiki/Stishovite" title="Stishovite">Stishovite</a></li>
<li><a href="/enwiki/wiki/Tridymite" title="Tridymite">Tridymite</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Cryptocrystalline" title="Cryptocrystalline">Cryptocrystalline</a></th><td class="navbox-list navbox-even hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a class="mw-selflink selflink">Chalcedony</a></li>
<li><a href="/enwiki/wiki/Chert" title="Chert">Chert</a></li>
<li><a href="/enwiki/wiki/Flint" title="Flint">Flint</a></li>
<li><a href="/enwiki/wiki/Jasper" title="Jasper">Jasper</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Amorphous_solid" title="Amorphous solid">Amorphous</a></th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Fulgurite" title="Fulgurite">Fulgurite</a></li>
<li><a href="/enwiki/wiki/Lechatelierite" title="Lechatelierite">Lechatelierite</a></li>
<li><a href="/enwiki/wiki/Opal" title="Opal">Opal</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Miscellaneous</th><td class="navbox-list navbox-even hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Tiger%27s_eye" title="Tiger's eye">Tiger's eye</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Notable varieties</th><td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a class="mw-selflink selflink">Chalcedony</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Agate" title="Agate">Agate</a></li>
<li><a href="/enwiki/wiki/Carnelian" title="Carnelian">Carnelian</a></li>
<li><a href="/enwiki/wiki/Chrysoprase" title="Chrysoprase">Chrysoprase</a></li>
<li><a href="/enwiki/wiki/Heliotrope_(mineral)" title="Heliotrope (mineral)">Heliotrope</a></li>
<li><a href="/enwiki/wiki/Onyx" title="Onyx">Onyx</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Opal" title="Opal">Opal</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Fiorite" title="Fiorite">Fiorite</a></li>
<li><a href="/enwiki/wiki/Geyserite" title="Geyserite">Geyserite</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/enwiki/wiki/Quartz" title="Quartz">Quartz</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/enwiki/wiki/Amethyst" title="Amethyst">Amethyst</a></li>
<li><a href="/enwiki/wiki/Ametrine" title="Ametrine">Ametrine</a></li>
<li><a href="/enwiki/wiki/Herkimer_diamond" title="Herkimer diamond">Herkimer diamond</a></li>
<li><a href="/enwiki/wiki/Smoky_quartz" title="Smoky quartz">Smoky quartz</a></li>
<li><a href="/enwiki/wiki/Shocked_quartz" title="Shocked quartz">Shocked quartz</a></li>
<li><a href="/enwiki/wiki/Prasiolite" title="Prasiolite">Prasiolite</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr></tbody></table></div>
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Whether or not the change was made through a Tor exit node (tor_exit_node) | false |
Unix timestamp of change (timestamp) | 1551832696 |