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Halide

Comancheite

Hg²⁺₅₅N³⁻₂₄(NH₂,OH)₄(Cl,Br)₃₄
Hardness2
Crystal systemOrthorhombic
ClassHalide
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Comancheite specimen

Comancheite , Calcite Locality: Mariposa Mine (California Mountain Mine), Terlingua District, Brewster County, Texas, USA Original description: Yellow ball of comancheite crystals on calcite, field of view 4 mm. K. Nash specimen and photo. — Photo: Kelly Nash · CC BY 3.0

Comancheite

Comancheite is an IMA-recognized mineral species in the halide class, with the chemical formula Hg²⁺₅₅N³⁻₂₄(NH₂,OH)₄(Cl,Br)₃₄.

It crystallizes in the orthorhombic crystal system (space group Pnnm).

Key properties: Mohs hardness 2; specific gravity 7.7; Yellow-orange streak; Vitreous in crystals; resinous when massive luster; optically biaxial.

IMA symbol Cmc, IMA status: approved, named in 1980.

Found as a secondary mineral in an oxidized mercury deposit.

It is found associated with Calcite, goethite, hematite, quartz.

The name refers to the Comanche Indians, the first miners of the mercury deposits in which this mineral occurs.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more C minerals or help write this entry.