Chromium Mineral Data

Chromium Mineral Data

[Mineral Forums] [Minerals for Sale] [About Us] [En Espanol] [Mineral Gallery]
Fabre Minerals - Europe's first Internet mineral dealer, on the web since 1996

General Chromium Information

Chemical Formula:

Composition:

Molecular Weight = 52.00 gm

Chromium 100.00 % Cr

______

100.00 %

Empirical Formula:

Environment:

In heavy sands derived from the contact metamorphic zone between a siliceous marble and ultramafic rock.

IMA Status:

Approved IMA 1981

Locality:

Sichuan Province, China. Link to MinDat.org Location Data.

Name Origin:

From the Greek, chroma = "color", in allusion to the colorful salts of this element.

Synonym:

ICSD 64711

PDF 6-694

Chromium Image

Images:

Chromium

Comments: Small silvery-gray metallic grain of native chromium.
Location: Sichuan, China. Scale: Grain size 0.7 mm.
© Thomas Witzke / Abraxas-Verlag

Chromium Crystallography

Cell Dimensions:

a = 2.8839, Z = 2; V = 23.99 Den(Calc)= 7.20

Crystal System:

Isometric - HexoctahedralH-M Symbol (4/m 3 2/m) Space Group: I m3m

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

By Intensity(I/I_o): 2.039(1), 1.177(0.3), 0.912(0.2),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Wyckoff R W G , Crystal Structures , 1 (1963) p.7-83, Second edition. Interscience Publishers, New York, New York, Cubic closest packed, ccp, structure

View Additional jPOWD Structure files for Chromium
[1] [2]

Physical Properties of Chromium

Color:

White.

Density:

7.2

Diaphaniety:

Opaque

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Hardness:

7.5 - Garnet

Luster:

Metallic

Optical Properties of Chromium

RL Color:

White with a yellow tint.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Chromium in Air**
λ	R	∑ R(λ)
480 nm	65.30
546 nm	67.90
589 nm	68.80
656 nm	70.00

**Calculated Relative Intensity Colors of Chromium in Air**
Relative Intensity	0%	20%	40%	60%	80%	100%	120%	140%
R

Calculated Properties of Chromium

Electron Density:

r_electron=6.65 gm/cc
note: r_Chromium=7.20 gm/cc.

Fermion Index

Fermion Index = 0.095
Boson Index = 0.905

Photoelectric:

PE_Chromium= 23.26 barns/electron
U=PE_Chromium x r_electron= 154.63 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Chromium is Not Radioactive

Chromium Classification

Dana Class:

1.1.12.1 (1)Native Elements

(1.1)with metallic elements other than the platinum group

(1.1.12)Dana Group

1.1.12.1 Chromium Cr I m3m 4/m 3 2/m

1.1.12.2 Chromferide Fe3Cr1-x(x=0,6) P m3m 4/m 3 2/m

1.1.12.3 Ferchromide Cr3Fe1-x(x=0,6) P m3m 4/m 3 2/m

Strunz Class:

I/A.06-10 I - Elements

I/A - Metallic and intermetallic compounds, Carbides, Nitrides, Phosphides and Silicides

I/A.06 - Chromium series, Titanium-Chromferides

I/A.06-05 Titanium* Ti P 6₃/mmc 6/m 2/m 2/m

I/A.06-10 Chromium Cr I m3m 4/m 3 2/m

I/A.06-20 Ferchromide Cr3Fe1-x(x=0,6) P m3m 4/m 3 2/m

I/A.06-30 Chromferide Fe3Cr1-x(x=0,6) P m3m 4/m 3 2/m

Other Chromium Information

References:

NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)

See Also:

Links to other databases for Chromium :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - Google Images
5 - Google Scholar
6 - Handbook of Mineralogy (MinSocAm)
7 - Handbook of Mineralogy (UofA)
8 - MinDAT
9 - MinMax(Deutsch)
10 - MinMax(English)
11 - Mineralienatlas (Deutsch)
12 - QUT Mineral Atlas
13 - Ruff.Info
14 - WWW-MINCRYST

Search for Chromium using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Chromium :

AA Mineral Specimens

B & L Fine Minerals

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

MineralsWeb Fine Minerals

The GeoZone

Wrights Rock Shop

Translate Chromium Mineral Data :

Ask about Chromium 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 Chromium Specimen Label here :

Chromium

Cr
Dana No: 1.1.12.1 Strunz No: I/A.06-10
Locality:

Notes: