Examine individual changes

'{{for|the religious movement|Millerism}} {{for|the neighborhood in Gary|Miller Beach}} {{Infobox mineral | name = Millerite | category = [[Sulfide mineral]] | boxwidth = | image = Millerite-Quartz-232902.jpg | caption = Millerite needles in a quartz geode. Locality: Halls Gap, Lincoln County, Kentucky. Size: 4.0 x 3.5 x 3.0 cm | formula = NiS | strunz = 02.CC.20 | symmetry = Trigonal {{overline|3}}2/m | unit cell = a = 9.607 Å, c = 3.143 Å; Z=9 | colour = Pale brass-yellow to bronze-yellow, tarnishes to iridescence | habit = Typically acicular (needle-like) often in radial sprays - also massive | system = [[Trigonal]] Hexagonal Scalenohedral | cleavage = Perfect on {10{{overline|1}}1} and {01{{overline|1}}2} - obscured by typical form | fracture = Uneven | tenacity = Brittle; capillary crystals elastic | mohs = 3 - 3.5 | luster = Metallic | diaphaneity = Opaque | refractive = | pleochroism = | streak = Greenish black | gravity = 5.3 - 5.5 | melt = | solubility = | other = brittle and becomes magnetic on heating | references = <ref name=Handbook>http://rruff.geo.arizona.edu/doclib/hom/millerite.pdf Handbook of Mineralogy</ref><ref name=Mindat>http://www.mindat.org/min-2711.html Mindat</ref><ref name=Webmin>http://webmineral.com/data/Millerite.shtml Webmineral</ref><ref name=Hurlbut>Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., pp. 279-280, ISBN 0-471-80580-7 </ref> }} '''Millerite''' is a [[nickel]] [[sulfide mineral]], [[nickel|Ni]][[Sulfur|S]]. It is brassy in colour and has an [[Acicular (crystal habit)|acicular]] habit, often forming radiating masses and furry aggregates. It can be distinguished from pentlandite by crystal habit, its duller colour, and general lack of association with [[pyrite]] or [[pyrrhotite]]. == Paragenesis == Millerite is a common metamorphic mineral replacing [[pentlandite]] within [[serpentinite]] ultramafics. It is formed in this way by removal of sulfur from pentlandite or other nickeliferous sulfide minerals during [[metamorphism]] or [[metasomatism]]. Millerite is also formed from sulfur poor [[olivine]] [[cumulate rocks|cumulates]] by nucleation. Millerite is thought to form from sulfur and nickel which exist in pristine olivine in trace amounts, and which are driven out of the olivine during metamorphic processes. [[Magma]]tic olivine generally has up to ~4000&nbsp;ppm Ni and up to 2500&nbsp;ppm S within the [[crystal lattice]], as contaminants and substituting for other [[transition metal]]s with similar ionic radii (Fe²⁺ and Mn²⁺). [[Image:Millerite structure.jpg|thumb|left|Millerite structure]] During metamorphism, sulfur and nickel within the olivine lattice are reconstituted into metamorphic sulfide minerals, chiefly millerite, during serpentinization and [[talc carbonate]] alteration. When metamorphic olivine is produced, the propensity for this mineral to resorb sulfur, and for the sulfur to be removed via the concomittant loss of volatiles from the serpentinite, tends to lower sulfur [[fugacity]]. This forms disseminated needle like millerite crystals dispersed throughout the rock mass. Millerite may be associated with [[heazlewoodite]] and is considered a transitional stage in the metamorphic production of heazlewoodite via the above process. IM THAT BITCH == Economic importance == Millerite, when found in enough concentration, is a very important ore of [[nickel]] because, for its mass as a sulfide mineral, it contains a higher percentage of nickel than [[pentlandite]]. This means that, for every percent of millerite, an ore contains more nickel than an equivalent percentage of pentlandite sulfide. Millerite forms an important ore constituent of the Silver Swan, Wannaway, Cliffs, Honeymoon Well, Yakabindie and Mt Keith (MKD5) orebodies. It is an accessory mineral associated with nickel [[laterite]] deposits in [[New Caledonia]]. == Occurrence == [[File:Millerite-44389.jpg|thumb|Lustrous mass of intergrown millerite needles from Kalgoorlie, Western Australia. (size: 3.9 x 3.5 x 2.2 cm)]] Millerite is found as a metamorphic replacement of [[pentlandite]] within the Silver Swan nickel deposit, Western Australia, and throughout the many ultramafic serpentinite bodies of the [[Yilgarn craton|Yilgarn Craton]], [[Western Australia]], generally as a replacement of metamorphosed pentlandite. It is commonly found as radiating clusters of acicular needle-like crystals in cavities in sulfide rich [[limestone]] and [[dolomite]] or in [[geode]]s. It is also found in nickel-iron [[meteorite]]s, such as CK [[carbonaceous chondrites]].<ref>{{cite journal |title=Formation of opaque minerals in CK chondrites |first1=T. |last1=Geiger|first2=A.|last2=Bischoff |doi=10.1016/0032-0633(94)00173-O |journal=Planetary and Space Science |volume=43 |issue=3–4 |year=1995 |pages=485–498 |bibcode = 1995P&SS...43..485G }}</ref> Millerite was discovered by [[Wilhelm Haidinger]] in 1845 in the coal mines of [[Wales]]. It was named for British mineralogist [[William Hallowes Miller]]. The mineral is quite rare in specimen form, and the most common source of the mineral is the in Halls Gap area of [[Lincoln County, Kentucky]] in the [[United States]]. ==See also== *[[List of minerals]] *[[List of minerals named after people]] ==References== {{reflist}} ==External links== *[http://mineral.galleries.com/minerals/sulfides/millerit/millerit.htm Mineral galleries] *[http://www.uwrf.edu/~wc01/millerite.htm Wisconsin minerals] *[http://www.uky.edu/KGS/coal/webrokmn/pages/sulfides.html University of Kentucky, Kentucky Geological Survey, Sulfide Minerals] {{Commonscat}} [[Category:Nickel minerals]] [[Category:Sulfide minerals]] [[Category:Trigonal minerals]]'