Rosickýite
{{Short description|Native element mineral}}
{{Infobox mineral
| name = Rosickyite
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| image = Rosickýite.jpg
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| caption = Sharp yellow crystals of rosickyite on matrix from an unspecified off shore drill hole in the Pacific Ocean near California (Ventura County, California, United States of America).
| category = Native element mineral
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| formula = S
| strunz = 1.CC.05
| dana =
| system = Monoclinic
| class = Prismatic (2/m)
(same H-M symbol)
| symmetry = P2/c
| unit cell = a = 8.455(3) Å,
b = 13.052(2) Å
c = 9.267(3) Å;
β = 124.89(3)°; Z = 4
| color = Colorless to pale yellow, green tinge
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| habit = Equidimensional to thin tabular crystals, efflorescences
| twinning = On {101}, with twin lamellae parallel to [010]
| cleavage = None
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| mohs = 2 - 3
| luster = Adamantine
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| diaphaneity = Transparent to translucent
| gravity = 2.07
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| opticalprop = Biaxial (-)
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| references = [http://rruff.geo.arizona.edu/doclib/hom/rosickyite.pdf Handbook of Mineralogy][http://www.mindat.org/min-3458.html Rosickyite on Mindat.org][http://webmineral.com/data/Rosickyite.shtml#.UEykObJmReo Rosickyite on Webmineral.com]
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Rosickyite is a rare native element mineral that is a polymorph of sulfur. It crystallizes in the monoclinic crystal system and is a high temperature, high density polymorph. It occurs as soft, colorless to pale yellow crystals and efflorescences.
It was first described in 1930 for an occurrence in Havirna, near Letovice, Moravia, Czech Republic. It was named for Vojtĕch Rosický (1880–1942), of Masaryk University, Brno.
Rosickyite occurs as in Death Valley within an evaporite layer produced by a microbial community. The otherwise unstable polymorph was produced and stabilized within a cyanobacteria dominated layer.Susanne Douglas and Heixong Yang, Mineral biosignatures in evaporites: Presence of rosickyite in an endoevaporitic microbial community from Death Valley, California, Geology, Dec. 2002, v 30, pp1075-1078
References
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Category:Native element minerals