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:

Hg₁₃Cl₇BrO₉

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

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 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:

PE_Comancheite=1,460.84 barns/electron
U=PE_Comancheite x rElectron 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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Print or Cut-and-Paste your Comancheite Specimen Label here :

Comancheite

Hg13(Cl,Br)8O9
Dana No: 10.05.05.01 Strunz No: 03.DD.65
Locality:

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