Chromatite Mineral Data

General Chromatite Information

Chemical Formula:

CaCrO4

Composition:

Molecular Weight = 156.07 gm

Calcium 25.68 % Ca 35.93 % CaO

Chromium 33.32 % Cr 64.07 % CrO₃

Oxygen 41.01 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca(CrO₄)

Environment:

Formed in an arid climate along fractures in limestones and marls by ascending ground water, the chromium derived from underlying bituminous phosphatic marls.

IMA Status:

Approved IMA 1963

Locality:

Maaleh Adumim, along the Jerusalem-Jericho highway, and in the Hatrurim Formation, Israel. Link to MinDat.org Location Data.

Name Origin:

Named as a chromate.

Synonym:

ICSD 30283

PDF 8-458

Chromatite Image

Images:

Chromatite

Comments: Yellow, powdery coating of chromatite over carbonate rock. Associated minerals in the crust are halite and fluorapatite.
Location: Ma'aleh Adumim, Hatrurim formation, West Bank, Palestine. Scale: Box Size 29x29 mm.
© Pavel M. Kartashov

Chromatite Crystallography

Axial Ratios:

a:c = 1:0.86854

Cell Dimensions:

a = 7.242, c = 6.29, Z = 4; V = 329.89 Den(Calc)= 3.14

Crystal System:

Tetragonal - Ditetragonal DipyramidalH-M Symbol (4/m 2/m 2/m) Space Group: I 4₁/amd

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

By Intensity(I/I_o): 3.62(1), 2.68(0.55), 1.85(0.45),

Physical Properties of Chromatite

Cleavage:

None

Color:

Lemon.

Density:

3.142

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Streak:

light yellow

Optical Properties of Chromatite

Gladstone-Dale:

CI meas= 0.073 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.072 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2691,KPDmeas= 0.2689,KC= 0.2901
Ncalc = 1.91

Optical Data:

Uniaxial (+), w=1.81-1.85, e=1.84-1.88, bire=0.0300.

Calculated Properties of Chromatite

Electron Density:

Bulk Density (Electron Density)=3.06 gm/cc
note: Specific Gravity of Chromatite =3.14 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Chromatite= 10.71 barns/electron
U=PE_Chromatite x rElectron Density= 32.75 barns/cc.

Radioactivity:

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

Chromatite Classification

Dana Class:

35.03.02.01 (35)Anhydrous Chromates

(35.03)where A+ XO4

(35.03.02)Dana Group

35.03.02.01 Chromatite CaCrO4 I 4₁/amd 4/m 2/m 2/m

Strunz Class:

07.FA.10 07 - SULFATES (SELENATES, TELLURATES)

07.F - Chromates

07.FA -Without additional anions

07.FA.10 Chromatite CaCrO4 I 4₁/amd 4/m 2/m 2/m

Other Chromatite Information

References:

NAME( AntBidBlaNic5) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Chromatite :
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

Search for Chromatite using:

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Mineral News Website Link
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Ask about Chromatite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Chromatite

CaCrO4
Dana No: 35.03.02.01 Strunz No: 07.FA.10
Locality:

Notes: