Rhomboclase

Summary

Rhomboclase is an acidic iron sulfate mineral with a formula reported as H5Fe3+O2(SO4)2·2(H2O)[4] or HFe(SO4)2·4(H2O).[2] It crystallizes in the orthorhombic system and typically occurs as tabular crystals with a rhombic outline.[4] It occurs as transparent colorless, blue, green, yellow or grey crystals with a vitreous to pearly luster.[3]

Rhomboclase
General
CategorySulfate mineral
Formula
(repeating unit)
H5Fe3+O2(SO4)2·2(H2O)
IMA symbolRbc[1]
Strunz classification7.CB.55
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPnma
Identification
Colorblue, colourless, white, yellow, light green, grey
Lustersub-Vitreous, Pearly
Streakwhite
Diaphaneitytransparent
References[2][3]

Rhomboclase forms within the oxidizing environment of pyrite rich ore deposits and is reported as a post mine mineral of arid regions.[4]

It was first described in 1888 for an occurrence in Slovakia and was named from Latin, rhombus, rhomb, and Greek klasis, to break, for its crystal form and perfect basal cleavage.[2]

References edit

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b c http://www.mindat.org/min-3410.html Mindat
  3. ^ a b http://webmineral.com/data/Rhomboclase.shtml Webmineral data
  4. ^ a b c http://www.handbookofmineralogy.org/pdfs/rhomboclase.pdf Handbook of Mineralogy