Coquandite Mineral Data

General Coquandite Information

Chemical Formula:

Sb6O8(SO4)•(H2O)

Composition:

Molecular Weight = 972.57 gm

Antimony 75.11 % Sb 89.92 % Sb₂O₃

Hydrogen 0.21 % H 1.85 % H₂O

Sulfur 3.30 % S 8.23 % SO₃

Oxygen 21.39 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Sb₆O₈(SO₄)•(H₂O)

Environment:

Probably produced by action of H2SO4 on stibnite, in a stibnite vein in silicified limestone

IMA Status:

Approved IMA 1992

Locality:

Cetine mine, 20 km southwest of Siena, and the Pereta mine, Scansano, Tuscany, Italy. Link to MinDat.org Location Data.

Name Origin:

Named for Henri-Jean-Baptiste Coquand (1813-1881), Professor of Geology and Mineralogy, University of Marseilles, Marseilles, France

Synonym:

IMA1991-024

Coquandite Image

Images:

Coquandite

Comments: Silky coquandite with stibnite.
Location: Pereta mine, Grosseto, Tuscany, Italy. Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag

Coquandite Crystallography

Axial Ratios:

a:b:c =0.384:1:0.38

Cell Dimensions:

a = 11.434, b = 29.77, c = 11.314, Z = 12; alpha = 91.073°, beta = 119.245°, gamma = 92.82° V = 3,355.64 Den(Calc)= 5.77

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

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

By Intensity(I/I_o): 3.092(1), 3.304(0.93), 6.81(0.67),

Physical Properties of Coquandite

Cleavage:

{???} Perfect

Color:

Colorless, White.

Diaphaneity:

Transparent to Translucent

Hardness:

3-4 - Calcite-Fluorite

Luster:

Adamantine

Streak:

white

Optical Properties of Coquandite

Gladstone-Dale:

CI calc= 0.081 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1869,KC= 0.2034
Ncalc = 2.18

Optical Data:

Biaxial (+), b=2.08, 2V(Meas)=80-85.

Calculated Properties of Coquandite

Electron Density:

Bulk Density (Electron Density)=5.09 gm/cc
note: Specific Gravity of Coquandite =5.78 gm/cc.

Fermion Index:

Fermion Index = 0.0003502393
Boson Index = 0.9996497607

Photoelectric:

PE_Coquandite= 251.19 barns/electron
U=PE_Coquandite x rElectron Density=1,277.87 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Coquandite is Not Radioactive

Coquandite Classification

Dana Class:

30.01.18.01 (30)Anhydrous Sulfates Containing Hydroxyl or Halogen

(30.01)where (A B)m (XO4)p Zq where m:p>2:1

(30.01.18)Dana Group

30.01.18.01 Coquandite Sb6O8(SO4)•(H2O) P1 1

Strunz Class:

07.DE.35 07 - SULFATES (SELENATES, TELLURATES)

07.D - Sulfates (selenates, etc.) with additional anions, with H2O

07.DE -With only medium-sized cations; unclassified

07.DE.35 Coquandite Sb6O8(SO4)•(H2O) P1 1

Other Coquandite Information

References:

NAME( AntBidBlaNic5) PHYS. PROP.(37th List of New Min.,Min. Mag.,1996) OPTIC PROP.(37th List of New Min.,Min. Mag.,19)

See Also:

Links to other databases for Coquandite :
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 Coquandite Specimen Label here :

Coquandite

Sb6O8(SO4)•(H2O)
Dana No: 30.01.18.01 Strunz No: 07.DE.35
Locality:

Notes: