Comancheite Mineral Data
General Comancheite Information
Chemical Formula:
Hg13(Cl,Br)8O9
Composition:
Molecular Weight = 3,079.74 gm
Mercury 84.67 % Hg 91.43 % HgO
Bromine 2.59 % Br 2.59 % Br
- %
Br -0.26 % -O=Br2
Chlorine 8.06 % Cl 8.06 % Cl
- %
Cl -1.82 % -O=Cl2
Oxygen 4.68 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Hg13 Cl7 BrO9
Environment:
Encrusting calcite.
IMA Status:
Approved IMA 1981
Locality:
Mariposa mine, Terlingua district, Brewster County, Texas, USA. Link to MinDat.org Location Data.
Name Origin:
Named for the Comanche Indians, who were the first miners in the Terligua district, using cinnabar for war paint.
Comancheite Image
Images:
Comancheite
Comments: Small orange crystals of comancheite on matrix.
Location: Mariposa mine, Terlingua, Terlingua district, Brewster County, Texas, USA.
Scale: Picture size 1.4 mm.
© Thomas Witzke / Abraxas-Verlag
Comancheite Crystallography
Axial Ratios:
a:b:c =0.8507:1:0.3085
Cell Dimensions:
a = 18.41, b = 21.64, c = 6.677, Z = 4; V = 2,660.07 Den(Calc)= 7.69
Crystal System:
Orthorhombic Space Group: Pnnm,Pnn2
X Ray Diffraction:
By Intensity(I/Io ): 2.669(1), 2.878(0.8), 5.68(0.7),
Physical Properties of Comancheite
Cleavage:
{001} Distinct, {110} Distinct
Color:
Yellow, Orange red, Red.
Density:
7.7
Fracture:
Brittle - Generally displayed by glasses and most non-metallic minerals.
Habit:
Acicular - Occurs as needle-like crystals.
Habit:
Stellate - Occurs as spherical, radial aggregates radiating from a "star" like point.
Hardness:
2 - Gypsum
Luster:
Vitreous - Resinous
Streak:
orange
Optical Properties of Comancheite
Gladstone-Dale:
CI meas = 0.29 (Poor) - where the CI = (1-KPDmeas /KC ) CI calc = 0.289 (Poor) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.1021,KPDmeas = 0.1019,KC = 0.1435 Ncalc = 2.1 - 2.11
Optical Data:
Biaxial (?), a=1.78, g=1.79, bire=0.0100
Calculated Properties of Comancheite
Electron Density:
Bulk Density (Electron Density)=6.32 gm/cc note: Specific Gravity of Comancheite =7.69 gm/cc.
Fermion Index:
Fermion Index = 0.25 Boson Index = 0.75
Photoelectric:
PEComancheite =1,460.84 barns/electronU=PEComancheite x r Electron Density=9,235.92 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Comancheite is Not Radioactive
Comancheite Classification
Dana Class:
10.05.05.01 (10) Oxyhalides and Hydroxyhalides
(10.05) where Am (O,OH)p Xq
(10.05.05) Dana Group
10.05.05.01 Comancheite Hg13(Cl,Br)8O9 Pnnm,Pnn2 Ortho
Strunz Class:
03.DD.65 03 - HALIDES
03.D - Oxyhalides, Hydroxyhalides and Related Double Halides
03.DD -With Hg
03.DD.65 Comancheite Hg13(Cl,Br)8O9 Pnnm,Pnn2 Ortho
Other Comancheite Information
References:
NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)
See Also:
Links to other databases for Comancheite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
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Comancheite
Hg13(Cl,Br)8O9
Dana No: 10.05.05.01 Strunz No: 03.DD.65
Locality:
Notes:
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