Editing Greenockite

{{Infobox mineral
| name        = Greenockite
| category    = [[Sulfide mineral]]
| image       = Greenockite-259580.jpg
| imagesize   = 260px
| caption     = Greenockite crystals from Tsumeb Mine, Namibia (Picture width 1 mm)
| formula     = CdS
| IMAsymbol   = Gnk<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}</ref>
| molweight   = 144.48
| strunz      = 2.CB.45
| system      = [[Hexagonal crystal system|Hexagonal]]
| class       = Dihexagonal pyramidal (6mm) <br/><small>(same [[H-M symbol]])</small>
| symmetry    = ''P6''<sub>3</sub>mc
| unit cell   = a = 4.136 <br/>c = 6.713&nbsp;[Å]; Z&nbsp;=&nbsp;2
| color       = Honey yellow, citron yellow, orange yellow 
| habit       = Colloform – forming from a gel or colloidal mass; encrustations – forms crust-like aggregates on matrix; radial – crystals radiate from a center without producing stellar forms (e.g. stibnite)
| twinning    = Rare on {11{{overline|2}}2} forming trillings
| cleavage    = Distinct on {11{{overline|2}}2}, imperfect on {0001}  
| fracture    = Conchoidal 
| tenacity    = Brittle 
| mohs        = 3.0–3.5
| luster      = Adamantine to resinous
| refractive  = n<sub>ω</sub> = 2.529 n<sub>ε</sub> = 2.506
| opticalprop = Uniaxial (−)
| birefringence = δ = 0.023
| pleochroism = Weak
| streak      = Yellow orange to brick red
| gravity     = 4.8–4.9 
| melt        = 
| fusibility  = 
| diagnostic  = 
| solubility  = 
| diaphaneity = Nearly opaque to translucent
| fluorescence = yellow-orange fluorescence under UV when rich in zinc{{citation needed|date=May 2014}}
| other       = Toxic
| references  = <ref name=HBM>[http://rruff.geo.arizona.edu/doclib/hom/greenockite.pdf Handbook of Mineralogy]</ref><ref name=Mindat>[http://www.mindat.org/min-1746.html Mindat]</ref><ref name=Webmin>[http://webmineral.com/data/Greenockite.shtml Webmineral]</ref>
| SMILES      = [CdH2-2]1[S+2]47[CdH-2]2[S+2][CdH-2]3[S+2]8([CdH2-2][SH+2]([CdH2-2]4)[CdH2-2]6)[CdH-2]4[S+2][CdH-2]5[S+2]6([CdH2-2]6)[Cd-2]78[S+2]78[CdH-2]([SH+2]69)[SH+2]5[CdH2-2][SH+2]4[CdH-2]7[SH+2]3[CdH2-2][SH+2]2[CdH-2]8[SH+2]1[CdH2-2]9
| Jmol        = [CdH2-2]1[SH+2]([CdH2-2]6)[CdH2-2][SH+2]7[CdH-2]2[S+2][Cd-2]3([S+2][CdH-2]9[S+2]5)[S+2]18[Cd-2]45[S+2][CdH-2]5[SH+2]6[Cd-2]78[S+2]78[CdH2-2][SH+2]5[CdH2-2][S+2]4([CdH2-2][SH+2]9[CdH2-2]4)[CdH-2]7[S+2]34[CdH2-2][SH+2]2[CdH2-2]8

}}

'''Greenockite''', also ''cadmium blende'' or ''cadmium ochre'' (obsolete) is a rare [[cadmium]] bearing metal [[sulfide mineral]]  consisting of [[cadmium sulfide]] (CdS) in crystalline form. Greenockite crystallizes in the [[Hexagonal crystal system|hexagonal]] system. It occurs as massive encrustations and as hemimorphic six-sided pyramidal crystals which vary in color from a honey yellow through shades of red to brown. The [[Mohs hardness]] is 3 to 3.5 and the [[specific gravity]] is 4.8 to 4.9.

Greenockite belongs to the [[wurtzite]] group  and is isostructural with it at high temperatures. It is also isostructural with [[sphalerite]] at low temperatures. It occurs with other sulfide minerals such as sphalerite and [[galena]], and is the only ''ore mineral'' of cadmium. Most cadmium is recovered as a byproduct of copper, zinc, and lead mining. It is also known from the lead-zinc districts of the central [[United States]].

It was first recognized in 1840 in [[Bishopton, Renfrewshire|Bishopton]], [[Scotland]], during the cutting of a tunnel for the [[Glasgow, Paisley and Greenock Railway]]. The mineral was named after the land owner [[Charles Cathcart, 2nd Earl Cathcart|Lord Greenock]] (1783–1859).<ref name=Mindat/><ref>{{Cite web |url=http://www.hmag.gla.ac.uk/John/huntmin/greenock.htm |title=Glasgow museum site |access-date=2005-08-02 |archive-url=https://web.archive.org/web/20120716222609/http://www.hmag.gla.ac.uk/John/huntmin/greenock.htm |archive-date=2012-07-16 |url-status=dead }}</ref>

==Use==
Greenockite, also known as "cadmium ochre", was used as a yellow pigment prior to cadmium being recognized as a [[toxic]] element. The extracted cadmium has various industrial use, such as electrical nickel-cadmium (NiCd) [[rechargeable batteries]], [[electroplating]], high temp alloys, plating steel and other metals that corrode easily, and use in control rods for some nuclear reactors.  

==References==
{{Reflist}}
*[https://web.archive.org/web/20051106000206/http://mineral.galleries.com/minerals/sulfides/greenock/greenock.htm Mineral galleries]

==External links==
*{{Commons category-inline}}

[[File:Greenockite-3D-balls.png|thumb|left|[[Crystal structure]] of greenockite]]

[[Category:Cadmium minerals]]
[[Category:Sulfide minerals]]
[[Category:Renfrewshire]]
[[Category:Hexagonal minerals]]
[[Category:Minerals in space group 186]]
[[Category:Blendes]]

{{-}}
{{sulfide-mineral-stub}}