Kratochvílite
General
CategoryOrganic mineral
Formula
(repeating unit)
C13H10
IMA symbolKtc[1]
Strunz classification10.BA.25
Crystal systemOrthorhombic
Crystal classPyramidal (mmm)
Space groupOrthorhombic
H-M symbol: (mm2)
Space group: Pnam
Identification
ColorWhite
StreakWhite
Optical propertiesBiaxial (+)
Refractive indexnα = 1.578 nβ = 1.663 nγ = 1.919
Birefringenceδ = 0.341
References[2][3][4]

Kratochvilite is a rare organic mineral formed by combustion of coal or pyritic black shale deposits. It is a hydrocarbon with the formula of either C13H10 or (C6H4)2CH2. It is a polymorph of the aromatic hydrocarbon fluorene. It forms white, yellow to brown crystals in the orthorhombic system which occur often as a druzey encrustation. It has a specific gravity of 1.21 and a Mohs hardness of 1 to 2.

It was first described from the Nejedly mine in Bohemia, Czech Republic in 1937.[3]

References

  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. Kratochvilite data on Webmineral
  3. 1 2 Mindat.org
  4. "The Handbook of Mineralogy" (PDF). Archived from the original (PDF) on 2016-03-03. Retrieved 2017-09-08.


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