Rosickýite

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.[1][2]

Rosickyite
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).
General
CategoryNative element mineral
Formula
(repeating unit)
S
Strunz classification1.CC.05
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP2/c
Unit cella = 8.455(3) Å,
b = 13.052(2) Å
c = 9.267(3) Å;
β = 124.89(3)°; Z = 4
Identification
ColorColorless to pale yellow, green tinge
Crystal habitEquidimensional to thin tabular crystals, efflorescences
TwinningOn {101}, with twin lamellae parallel to [010]
CleavageNone
Mohs scale hardness2 - 3
LusterAdamantine
DiaphaneityTransparent to translucent
Specific gravity2.07
Optical propertiesBiaxial (-)
References[1][2][3]

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.[1][2]

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.[4]

References

  1. Handbook of Mineralogy
  2. Rosickyite on Mindat.org
  3. Rosickyite on Webmineral.com
  4. 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
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