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[ 0 => '{{short description|Carbide mineral; polytypes: 10R, 15R, 33R, 5H}}', 1 => '{{Infobox mineral', 2 => '| name = Moissanite', 3 => '| category = [[Mineral]] species', 4 => '| image = Moissanite-USGS-20-1001d-14x-.jpg', 5 => '| imagesize = 260px', 6 => '| caption = ', 7 => '| formula = SiC', 8 => '| molweight = ', 9 => '| strunz = 1.DA.05', 10 => '| system = 6H polytype, most common: [[Hexagonal crystal system|hexagonal]]', 11 => '| class = 6H polytype: dihexagonal pyramidal (6mm) <br/>[[H-M symbol]]: (6mm)', 12 => '| symmetry = 6H polytype: ''P6''₃mc', 13 => '| color = Colorless, green, yellow', 14 => '| habit = Generally found as inclusions in other minerals ', 15 => '| twinning = ', 16 => '| cleavage = (0001) indistinct ', 17 => '| fracture = Conchoidal – fractures developed in brittle materials characterized by smoothly curving surfaces, e.g., quartz', 18 => '| mohs = 9.5 ', 19 => '| luster = Adamantine to metallic ', 20 => '| refractive = n_ω=2.654 n_ε=2.967, [[Birefringence]] 0.313 (6H form)', 21 => '| opticalprop = ', 22 => '| birefringence = ', 23 => '| fluorescence= orange-red', 24 => '| pleochroism = ', 25 => '| streak = greenish gray', 26 => '| gravity = 3.218–3.22', 27 => '| melt = 2730 °C (decomposes)', 28 => '| fusibility = ', 29 => '| diagnostic = ', 30 => '| solubility = none', 31 => '| diaphaneity = transparent', 32 => '| other = Not radioactive, non-magnetic ', 33 => '| references = <ref>[http://www.webmineral.com/data/Moissanite.shtml Moissanite]. Webmineral</ref><ref>[http://www.mindat.org/min-2743.html Moissanite]. Mindat</ref><ref name=Handbook>Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W. and Nichols, Monte C. (eds.) [http://www.handbookofmineralogy.org/pdfs/moissanite.pdf "Moissanite"]. ''Handbook of Mineralogy''. Mineralogical Society of America</ref>', 34 => '}}', 35 => '', 36 => ''''Moissanite''' ({{IPAc-en|ˈ|m|ɔɪ|s|ən|aɪ|t}})<ref>{{OED|Moissanite}}</ref> is naturally occurring [[silicon carbide]] and its various crystalline [[Polymorphism (materials science)|polymorphs]]. It has the chemical formula SiC and is a rare mineral, discovered by the French chemist [[Henri Moissan]] in 1893. Silicon carbide is useful for commercial and industrial applications due to its hardness, optical properties and thermal conductivity.', 37 => '', 38 => '== Background ==', 39 => 'Mineral moissanite was discovered by Henri Moissan while examining rock samples from a meteor crater located in [[Canyon Diablo (canyon)|Canyon Diablo]], [[Arizona]], in 1893. At first, he mistakenly identified the crystals as diamonds, but in 1904 he identified the crystals as silicon carbide.<ref name = xu>{{cite journal|author = Xu J. |author2=Mao H. |last-author-amp=yes |date = 2000| title = Moissanite: A window for high-pressure experiments|journal = [[Science (journal)|Science]]|volume = 290| pages = 783–787|doi = 10.1126/science.290.5492.783|pmid=11052937|issue=5492|bibcode = 2000Sci...290..783X }}</ref><ref>{{cite journal|author = Moissan, Henri |title = Nouvelles recherches sur la météorité de Cañon Diablo|date = 1904|journal = [[Comptes rendus]]|volume = 139| pages = 773–786| url = http://gallica.bnf.fr/ark:/12148/bpt6k30930/f773.table}}</ref> Artificial silicon carbide had been synthesized in the lab by [[Edward_Goodrich_Acheson|Edward G. Acheson]] just two years before Moissan's discovery.<ref>{{cite web|last1=Smith|first1=Kady|title=History and Applications of Silicon Carbide|url=http://blog.moissaniteco.com/history-and-applications-of-silicon-carbide/|publisher=Moissanite & Co|accessdate=2 February 2016}}</ref>', 40 => '', 41 => 'The mineral form of silicon carbide was named moissanite in honor of Moissan later on in his life. The discovery in the [[Canyon Diablo (meteorite)|Canyon Diablo meteorite]] and other places was challenged for a long time as [[Silicon carbide|carborundum]] contamination from man-made abrasive tools.<ref name = pierro>{{cite journal|author = Di Pierro S. |display-authors=4 |author2= Gnos E. |author3=Grobety B.H. |author4=Armbruster T. |author5=Bernasconi S.M. |author6=Ulmer P. |last-author-amp=yes |date = 2003|title = Rock-forming moissanite (natural α-silicon carbide)|journal = American Mineralogist|volume = 88|issue=11–12 |pages = 1817–1821|url = http://www.geoscienceworld.org/cgi/georef/2004018181|bibcode=2003AmMin..88.1817D|doi=10.2138/am-2003-11-1223}}</ref>', 42 => '', 43 => '== Geological occurrence ==', 44 => 'Until the 1950s, no other source for moissanite than meteorites had been encountered. Then, in 1958, moissanite was found in the [[Green River Formation]] in [[Wyoming]] and, the following year, as [[Inclusion (mineral)|inclusions]] in [[kimberlite]] from a diamond mine in [[Sakha Republic|Yakutia]].<ref>{{cite journal|journal = American Mineralogist|volume =48|pages = 620–634|date = 1963|title = Natural α–Silicon Carbide|author = Bauer, J.|author2=Fiala, J. |author3=Hřichová, R. |url=http://www.minsocam.org/msa/collectors_corner/arc/moissanite.htm}}</ref> Yet the existence of moissanite in nature was questioned as late as 1986 by the American geologist Charles Milton.<ref>{{cite journal|journal = American Mineralogist|volume =79|pages = 190–192|date = 1994|title = Memorial of Charles Milton April 25, 1896 – October 1990|url=http://www.minsocam.org/ammin/AM79/AM79_190.pdf|author = Belkin, H. E. |author2=Dwornik, E. J. }}</ref>', 45 => '', 46 => 'Moissanite, in its natural form, remains very rare. It has been discovered only in a few rocks, from [[upper mantle (Earth)|upper mantle]] rock to [[meteorite]]s. Discoveries show that it occurs naturally as inclusions in diamonds, [[xenolith]]s, and such [[ultramafic rock]]s as [[kimberlite]] and [[lamproite]].<ref name = pierro/> It has also been identified as [[presolar grains]] in [[carbonaceous chondrite]] meteorites.<ref name = sch>{{cite journal|author = Yokoyama, T. ', 47 => '| author2=Rai, V. K. ', 48 => '| author3=Alexander, C. M. O’D. ', 49 => '| author4=Lewis, R. S. ', 50 => '| author5=Carlson, R. W. ', 51 => '| author6=Shirey, S. B. ', 52 => '| author7=Thiemens, M. H. ', 53 => '| author8=Walker, R. J. |title = Nucleosynthetic Os Isotopic Anomalies in Carbonaceous Chondrites|url=http://www.lpi.usra.edu/meetings/lpsc2007/pdf/1151.pdf|journal = 38th Lunar and Planetary Science Conference |date=March 2007}}</ref>', 54 => '', 55 => '==Meteorites==', 56 => 'Analysis of silicon carbide grains found in the [[Murchison meteorite]] has revealed anomalous isotopic ratios of carbon and silicon, indicating an origin from outside the solar system.<ref>Kelly, Jim. [http://img.chem.ucl.ac.uk/www/kelly/history.htm The Astrophysical Nature of Silicon Carbide]. chem.ucl.ac.uk</ref> 99% of these silicon carbide grains originate around carbon-rich [[asymptotic giant branch]] stars. Silicon carbide is commonly found around these stars, as deduced from their infrared spectra.{{Citation needed|date=February 2016}}', 57 => '', 58 => '== Sources ==', 59 => 'All applications of silicon carbide today use [[Silicon carbide#Production|synthetic material]], as the natural material is very scarce.', 60 => '', 61 => 'Silicon carbide was first synthesized by [[Jöns Jacob Berzelius]], who is best known for his discovery of [[silicon]].<ref name = saddow>{{cite book| author = Saddow S.E. |author2=Agarwal A. |last-author-amp=yes |date = 2004| title = Advances in Silicon Carbide Processing an Applications|publisher = Artech House Inc.|url = https://books.google.com/books?id=2jSPO_JtQwEC|isbn = 978-1-58053-740-7}}</ref> Years later, [[Edward Goodrich Acheson]] produced viable minerals that could substitute for diamond as an abrasive and cutting material. This was possible, as moissanite is one of the hardest substances known, with a hardness below that of [[diamond]] and comparable with those of cubic [[boron nitride]] and [[boron]].', 62 => '', 63 => 'Pure synthetic moissanite can be made from [[thermal decomposition]] of the preceramic polymer [[poly(methylsilyne)]], requiring no binding matrix, ''e.g.'', cobalt metal powder.', 64 => '', 65 => '== Physical properties ==', 66 => '{{main article|Silicon carbide}}', 67 => 'The crystalline structure is held together with strong [[covalent bonding]] similar to diamonds,<ref name = xu/> that allows moissanite to withstand high pressures up to 52.1 [[gigapascal]]s.<ref name = xu/><ref name = zhang>{{cite journal|author = Zhang J. |display-authors=4 |author2= Wang L. |author3=Weidner D.J. |author4=Uchida T. |author5=Xu J. |last-author-amp=yes |date = 2002| title = The strength of moissanite |journal = American Mineralogist|volume = 87|issue=7 | pages = 1005–1008 |url = http://www.minsocam.org/msa/AmMin/toc/Abstracts/2002_Abstracts/July02_Abstracts/Zhang_p1005_02.pdf|bibcode=2002AmMin..87.1005Z|doi=10.2138/am-2002-0725}}</ref> Colors vary widely and are graded from D to K range on the [[Diamond color|diamond color grading scale]].<ref name = Read>{{cite book| author = Read P.|date = 2005| title = Gemmology |publisher = Elsevier Butterworth-Heinemann| place = Massachusetts|url = https://books.google.com/books?id=t-OQO3Wk-JsC| isbn = 978-0-7506-6449-3}}</ref>', 68 => '', 69 => '== Applications ==', 70 => '{{main article|Silicon carbide#Uses}}', 71 => '[[File:Moissanite_ring_natural_light.jpg|thumb|right|A moissanite engagement ring]]', 72 => 'Moissanite was introduced to the jewelry market in 1998 after [[Charles & Colvard]], formerly known as C3 Inc., received patents to create and market lab-grown silicon carbide gemstones, becoming the first firm to do so. Charles & Colvard currently makes and distributes moissanite jewelry and loose gems under the trademarks Forever One, Forever Brilliant and Forever Classic.<ref>{{cite web|title=Moissanite Rights|url=http://www.professionaljeweler.com/archives/articles/1998/may98/0598press1.html|publisher=Professional Jeweler Magazine|accessdate=24 October 2012|date=May 1998}}</ref> Other manufacturers market silicon carbide gemstones under trademarked names such as Amora. Moissanite is regarded as a [[diamond alternative]], with some optical properties exceeding those of diamond. Its lower price and less exploitative mining practices necessary to obtain it make it a popular alternative to diamonds. Due in part to the similar thermal conductivity of moissanite and diamond, it is a popular target for scams; however, higher electrical conductivity and [[birefringence]] of moissanite may alert a buyer to fraud. In addition, [[thermochromism]] is exhibited in moissanite, such that heating it gradually will cause it to change color starting at around {{convert|65|C|abbr=on|-1}}. This color change can be diagnostic for distinguishing diamond from moissanite, although birefringence and electrical conductivity differential are more practical diagnostic differentiators.<ref>[http://www.gemsociety.org/article/diamond-look-alike-comparison-chart/ Diamond Look-Alike Comparison Chart]. International Gem Society</ref> On the [[Mohs scale of mineral hardness]] it is a 9.5, with a diamond being a 10.<ref name=Handbook/> In many developed countries, the use of moissanite in jewelry was controlled by the patents held by Charles & Colvard; these patents expired in August 2015 for the United States, and in 2016 in most other countries except Mexico, where it remained under patent until 2018.<ref>Hunter, Charles Eric and Verbiest, Dirk (1995-08-31) {{US Patent|5762896}} "Single crystal gems hardness, refractive index, polishing and crystallization "</ref><ref>Hunter, Charles Eric and Verbiest, Dirk (1995-08-31) {{US Patent|5723391}} "Silicon carbide gemstones"</ref><ref>{{cite web|title=Moissanite Gem Patent Restrictions by Country and Year of Expiration|url=http://betterthandiamond.com/pages/Moissanite-Gem-Patent-restrictions-by-country-and-year-of-expiration.html|work=BetterThanDiamond}}</ref>', 73 => '', 74 => 'Because of its hardness, it can be used in high-pressure experiments, as a replacement for diamond (see [[diamond anvil cell]]).<ref name = xu/> Since large diamonds are usually too expensive to be used as anvils, synthetic moissanite is more often used in large-volume experiments. Synthetic moissanite is also interesting for [[electronics|electronic]] and thermal applications because its [[thermal conductivity]] is similar to that of diamonds.<ref name = zhang/> High power silicon carbide electronic devices are expected to find use in the design of protection circuits used for motors, [[actuator]]s, and energy storage or pulse power systems.<ref name=baliga>{{cite journal|last=Bhatnagar|first=M.|author2=Baliga, B.J.|title=Comparison of 6H-SiC, 3C-SiC, and Si for power devices|journal=IEEE Transactions on Electron Devices|date=1993|volume=40|issue=3|pages=645–655|doi=10.1109/16.199372 |bibcode = 1993ITED...40..645B }}</ref> It also exhibits [[thermoluminescence]],<ref>{{cite journal|last1=Godfrey-Smith|first1=D.I.|title=Applicability of moissanite, a monocrystalline form of silicon carbide,to retrospective and forensic dosimetry|journal=Radiation Measurements|date=Aug 1, 2006|volume=Volume 41|issue=7|url=https://www.deepdyve.com/lp/elsevier/applicability-of-moissanite-a-monocrystalline-form-of-silicon-carbide-Uaw0AcXWN0|accessdate=23 December 2017}}</ref> making it useful in radiation [[dosimetry]].<ref>{{cite journal|last1=Bruzzia|first1=M.|last2=Navab|first2=F.|last3=Piniac|first3=S.|last4=Russoc|first4=S.|title=High quality SiC applications in radiation dosimetry|journal=Applied Surface Science|date=12 December 2001|volume=Volume 184|issue=1–4|pages=Pages 425–430|doi=10.1016/S0169-4332(01)00528-1|url=|bibcode=2001ApSS..184..425B}}</ref>', 75 => '', 76 => '==See also==', 77 => '*[[Charles & Colvard]]', 78 => '*[[Cubic zirconia]]', 79 => '*[[Diamond]]', 80 => '*[[Engagement ring]]', 81 => '*[[Fair trade]]', 82 => '*[[Glossary of meteoritics]]', 83 => '', 84 => '==References==', 85 => '{{Reflist|30em}}', 86 => '', 87 => '== Further reading ==', 88 => '* {{cite journal|last=Nassau|first=Kurt|date=1999|title=Moissanite: a new synthetic gemstone material|journal=Journal of Gemmology|volume=26|issue=7|pages= 425–438|url=http://www.moissaniteco.com/pdf/Synthetic-Moissanite-A-New-Man-Made-Jewel.pdf|doi=10.15506/JoG.1999.26.7.425}}', 89 => '*Diamond Wish. [https://www.diamondwish.com/blog/moissanite-vs-diamond/ "Moissanite vs. Diamond"] (GIA diamond expert explains the difference)', 90 => '', 91 => '== External links ==', 92 => '* {{commons category-inline|Moissanite}} ', 93 => '', 94 => '{{Meteorites}}', 95 => '', 96 => '[[Category:Carbide minerals]]', 97 => '[[Category:Hexagonal minerals]]', 98 => '[[Category:Meteorite minerals]]', 99 => '[[Category:Native element minerals]]' ]