Coquimbite Mineral Data

General Coquimbite Information

Chemical Formula:

Fe+++2(SO4)3•9(H2O)

Composition:

Molecular Weight = 562.02 gm

Iron 19.87 % Fe 28.41 % Fe₂O₃

Hydrogen 3.23 % H 28.85 % H₂O

Sulfur 17.12 % S 42.74 % SO₃

Oxygen 59.78 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe³⁺₂(SO₄)₃•9(H₂O)

Environment:

Water soluble efflorescence commonly produced by mine fires or other oxidation with iron sulfide minerals. Dimorphous with paracoquimbite.

IMA Status:

Valid Species (Pre-IMA) 1841

Locality:

Coquimbo province, Chile. Link to MinDat.org Location Data.

Name Origin:

Named for the locality.

Name Pronunciation:

Coquimbite + Pronunciation

Synonym:

ICSD 15182

PDF 44-1425

Coquimbite Image

Images:

Coquimbite

Comments: Brownish yellow tabular crystals of coquimbite.
Location: Lavender Pit, Bisbee, Cochise County, Arizona, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Images:

Goldichite Coquimbite Ferricopiapite

Comments: Prismatic to fibrous crystals of goldichite on white massive coquimbite with yellow ferricopiapite.
Location: Dexter No. 7 Mine, Calf Mesa, San Rafael Swell, Emery County, Utah, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Coquimbite

Comments: Coquimbite rosettes (small bumps) secondarily nucleated on a cryptocrystalline mass. AmMin, v90, p1734.
Location: Vents associated with underground coal fires in the Wuda coal bed of Inner Mongolia. Scale: See Image.
© American Mineralogist

Coquimbite Crystallography

Axial Ratios:

a:c = 1:1.56418

Cell Dimensions:

a = 10.922, c = 17.084, Z = 4; V = 1,764.92 Den(Calc)= 2.12

Crystal System:

Trigonal - Hexagonal Scalenohedral H-M Symbol (3 2/m) Space Group: P 3c

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

By Intensity(I/I_o): 8.26(1), 2.759(0.75), 5.45(0.65),

Forms:

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Forms: ( 1 1 1) ( 1 1 0) ( 0 1 0) ( 0 0 1)

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Physical Properties of Coquimbite

Cleavage:

{1011} Imperfect

Color:

Greenish white, Bluish white, Light violet, Yellowish white, Brownish white.

Density:

2 - 2.1, Average = 2.04

Diaphaneity:

Transparent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Massive - Granular - Common texture observed in granite and other igneous rock.

Habit:

Platy - Sheet forms (e.g. micas).

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

2 - Gypsum

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Coquimbite

Dichroism (e):

none.

Dichroism (w):

none.

Gladstone-Dale:

CI meas= -0.026 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= 0.008 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2611,KPDmeas= 0.27,KC= 0.2632
Ncalc = 1.53 - 1.56

Optical Data:

Uniaxial (+), w=1.55, e=1.557, bire=0.0070.

Calculated Properties of Coquimbite

Electron Density:

Bulk Density (Electron Density)=2.16 gm/cc
note: Specific Gravity of Coquimbite =2.12 gm/cc.

Fermion Index:

Fermion Index = 0.005788726
Boson Index = 0.994211274

Photoelectric:

PE_Coquimbite= 6.81 barns/electron
U=PE_Coquimbite x rElectron Density= 14.70 barns/cc.

Radioactivity:

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

Coquimbite Classification

Dana Class:

29.08.03.01 (29)Hydrated Acid and Sulfates

(29.08)where (A)2 (XO4)3 ï¿½ x(H2O)

(29.08.03)Dana Group

29.08.03.01 Coquimbite Fe2(SO4)3•9(H2O) P 3c 3 2/m

Strunz Class:

07.CB.50 07 - SULFATES (SELENATES, TELLURATES)

07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O

07.CB -With only medium-sized cations

07.CB.50 Coquimbite Fe2(SO4)3•9(H2O) P 3c 3 2/m

07.CB.50 Paracoquimbite Fe2(SO4)3•9(H2O) R 3 3

Other Coquimbite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

See Also:

Links to other databases for Coquimbite :
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
15 - WWW-MINCRYST

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Print or Cut-and-Paste your Coquimbite Specimen Label here :

Coquimbite

Fe+++2(SO4)3•9(H2O)
Dana No: 29.08.03.01 Strunz No: 07.CB.50
Locality:

Notes:

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