Tongbaite

Tongbaite
General
CategoryCarbide mineral
Formula
(repeating unit)
Cr3C2
IMA symbolTgb[1]
Strunz classification1.BA.15
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPnma
Unit cella = 5.52 Å, b = 11.48 Å
c = 2.82 Å; Z = 4
Identification
ColorPale brownish yellow; pale violet in reflected light
Crystal habitPrismatic crystals, pseudohexagonal
TenacityBrittle
Mohs scale hardness8.5
LusterMetallic
DiaphaneityOpaque
Specific gravity6.64 calculated
References[2][3][4]

Tongbaite is a rare mineral that has the chemical formula Cr3C2, or chromium carbide.

It was first described in 1983 for an occurrence in Liu village, Tongbai County (桐柏县), Henan Province, China and named for the locality.[3] It occurs in an ultramafic rock deposit.[2] It has also been found in the Tibet Autonomous Region and the Isovsky District, in the Urals of Russia.[3]

  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 Handbook of Mineralogy
  3. ^ a b c Mindat.org
  4. ^ Webmineral data