Kosmochlor
(repeating unit)NaCr3+Si2O67 IMA symbol Kos[1] Strunz classification 9.DA.25 Crystal system Monoclinic Crystal class Prismatic (2/m)
(same H-M symbol) Space group C2/c Unit cell a = 9.57, b = 8.71
c = 5.26 Å; β = 107.49°; Z = 4 Identification Color Emerald-green Crystal habit Prismatic crystals and fibrous aggregates Twinning Simple, lamellar on {100} and {001} Cleavage Good on {110} parting on {001} Mohs scale hardness 6 Luster Vitreous Streak Light green Diaphaneity Semitransparent Specific gravity 3.51-3.60 Optical properties Biaxial (-) Refractive index nα = 1.766 nγ = 1.781 Birefringence δ = 0.015 Pleochroism X = yellowish green; Y = blue-green, grass-green; Z = emerald-green Dispersion r > v References [2][3][4]
(same H-M symbol)
c = 5.26 Å; β = 107.49°; Z = 4
Kosmochlor is a rare chromium sodium clinopyroxene with the chemical formula NaCr3+Si2O6.
The name is from German kosmisch, for its occurrence in meteorites, and the Greek chlor, for green.[4] It was first reported in 1897 from the Toluca meteorite, Jiquipilco, Mexico.[2]
It occurs as a major constituent of some jadeitites and as an accessory mineral of some iron meteorites. Associated minerals include cliftonite (graphite), chromian diopside, troilite at Toluca; daubreelite, krinovite, roedderite, high albite, richterite, chromite (Canyon Diablo); and jadeite, chromite and chlorite (Burma).[3]
References
- ^ 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.
- ^ a b Kosmochlor on Mindat
- ^ a b Kosmochlor in the Handbook of Mineralogy
- ^ a b Kosmochlor on Webmin
- v
- t
- e
