{{Short description|Hydrotalcite group mineral}} {{Infobox mineral |boxbgcolor=#d177df| name = Stichtite | boxtextcolor = #fff | image = Stichtite- Lizardite.jpg | alt = | caption = Stichtite on serpentine, Dundas, Tasmania | category = Carbonate minerals | formula = Mg<sub>6</sub>Cr<sub>2</sub>CO<sub>3</sub>(OH)<sub>16</sub>·4H<sub>2</sub>O | IMAsymbol = Stt<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> | strunz = 5.DA.50 | dana = | system = Trigonal | class = Hexagonal scalenohedral ({{overline|3}}m) <br/>H-M symbol: ({{overline|3}} 2/m) | symmetry = ''R''{{overline|3}}m | unit cell = a = 6.19, c = 46.47 [Å]; Z = 3 | color = | colour = Lilac to rose-pink | habit = Fibrous to platy aggregates | twinning = | cleavage = Perfect on {0001} | fracture = | tenacity = flexible, not elastic | mohs = 1.5–2 | lustre = Waxy to resinous | streak = Very pale lilac to white | diaphaneity = Transparent | gravity = 2.16 | density = | polish = | opticalprop = Uniaxial (+) | refractive = n<sub>ω</sub> = 1.516 n<sub>ε</sub> = 1.542 | birefringence = δ = 0.026 | pleochroism = Weak; O = dark rose-pink to lilac E = light rose-pink to lilac | 2V = | dispersion = | extinction = | length fast/slow = | fluorescence = | absorption = | melt = | fusibility = | diagnostic = | solubility = | impurities = | alteration = | other = | prop1 = | prop1text = | references = <ref name=HBM>[http://rruff.info/doclib/hom/stichtite.pdf Stichtite data in the Handbook of Mineralogy]</ref><ref name=Mindat>[http://www.mindat.org/min-3784.html Stichtite on Mindat.org]</ref><ref name=Webmin>[http://webmineral.com/data/Stichtite.shtml#.U590bfldXfI Stichtite data on Webmineral.com]</ref> }}
'''Stichtite''' is a mineral, a carbonate of chromium and magnesium; formula Mg<sub>6</sub>Cr<sub>2</sub>CO<sub>3</sub>(OH)<sub>16</sub>·4H<sub>2</sub>O. Its colour ranges from pink through lilac to a rich purple colour. It is formed as an alteration product of chromite-containing serpentine. It occurs in association with barbertonite (the hexagonal polymorph of Mg<sub>6</sub>Cr<sub>2</sub>CO<sub>3</sub>(OH)<sub>16</sub>·4H<sub>2</sub>O), chromite and antigorite.<ref name=HBM/>
Discovered in 1910 on the west coast of Tasmania, Australia, it was first recognised by A.S. Wesley a former chief chemist with the Mount Lyell Mining and Railway Company, it was named after Robert Carl Sticht the manager of the mine.<ref> Tasmania Department of Mines, Geological Survey Record Number 9 ''Catalogue of the Minerals of Tasmania''. Revised edition 1970, page 96 </ref>
It is observed in combination with green serpentine at Stichtite Hill near the Dundas Extended Mine, Dundas – east of Zeehan, as well as on the southern shore of Macquarie Harbour. It is exhibited in the West Coast Pioneers Museum in Zeehan. The only commercial mine for stichtite serpentine is located on Stichtite Hill{{cn|date=November 2014}}. Stichtite has also been reported from the Barberton District, Transvaal; Darwendale, Zimbabwe; near Bou Azzer, Morocco; Cunningsburgh, the Shetland Islands of Scotland; Langban, Varmland, Sweden; the Altai Mountains, Russia; Langmuir Township, Ontario and the Megantic, Quebec; Bahia, Brazil; and the Keonjhar district, Orissa, India.<ref name=HBM/>
It is sometimes used as a gemstone.<ref>{{Cite web|url=https://www.gemdat.org/gem-3784.html|title=Stichtite gemstone information}}</ref>
<gallery widths="175px" heights="125px" > File:Stichtite on serpentine Basic hydrous magnesium chromate and carbonate New Amianthus Mine Transvaal South Africa 1623.jpg|Stichtite on serpentine, New Amianthus Mine, Transvaal South Africa </gallery>
==References== {{reflist}}
==External links== {{Commonscat}} * http://www.asap.unimelb.edu.au/bsparcs/biogs/P002619b.htm Sticht, Robert Carl – Bright Sparcs Biographical entry
Category:Magnesium minerals Category:Chromium minerals Category:Carbonate minerals Category:Hydroxide minerals Category:Tetrahydrate minerals Category:Western Tasmania Category:Trigonal minerals Category:Minerals in space group 166 Category:Gemstones Category:Minerals described in 1910