Images
Formula: Cr
Native element, transition metal
Crystal System: Isometric
Specific gravity: 7.17 measured, 7.20 calculated
Hardness: 9
Colour: White
Melting point: 1907oC
Boiling point: 2670oC
Environments
Chromium is seldom found in the native state. The main ore is chromite. Abundance in the
Earth’s crust is 102 parts per million by mass, 40 parts per million by moles, and abundance in the Solar System is 20 parts per million
by mass, 0.4 parts per million by moles
(ChC).
Localities
In Liaoning Province,China, native chromium has been found in a kimberlite pipe
(HOM).
At the Yangliuping Cu-Ni-PGE deposit, Danba county, Garzê Autonomous Prefecture, Sichuan, China, native chromium has been found
in heavy sands derived from the contact metamorphic zone between a
siliceous marble and ultramafic rock. it is
finely granular with grain size about 20 pm, and closely associated with danbaite, which forms rims
around chromium. Other associated minerals include pyrrhotite,
pentlandite, chalcopyrite,
pyrite, sulphosalts and platinum group minerals
(AM 67.854-855, HOM).
At the type locality, the Anduo Cr deposit, Amdo county, Nagchu Prefecture, Tibet, China, native chromium is found in Heavy sands
derived from a contact metamorphic zone between siliceous
marble and ultramafic rock
(Mindat, Webmin).
At the Luobusha ophiolite, Qusum county, Shannan Prefecture, Tibet, China, native chromium is found in podiform
chromitites
(HOM).
At the Gavasai ore field, Chatkal district, Jalal-Abad Region, Kyrgyzstan, native chromium is found in
ultramafic dike rocks with cohenite,
moissanite, ilmenite and
titanite
(HOM).
In the Far-Eastern Economic Region, Russia, native chromium is found in in
serpentinite in
dunite–peridotite
(HOM).
At the Udachnaya open-pit mine, Daldyn, Mirninsky District, Sakha Republic, Russia, native chromium is found in
kimberlite as inclusions in diamonds
(HOM, Dana).
Chromium-bearing minerals include:
Nitrides
carlsbergite
Sulphides
daubréelite
zolenskyite
Oxides
chenmingite
crichtonite
davidite-(Ce)
davidite-(La)
eskolaite
hemleyite
magnesiochromite
mcconnellite
senaite
Oxide-Hydroxides
bracewellite
guyanaite
Hydroxides
woodallite
Carbonates
liudongshengite
Sulphates
evanichite
redingtonite
Chromates
chromatite
crocoite
edoylerite
ellinaite
hemihedrite
iranite
phoenicochroite
wattersite
Phosphates
vauquelinite
Arsenates
fornacite
Nesosilicates
uvarovite
Phyllosilicates
chromphyllite
Cyclosilicates
oxy-chromium-dravite
Back to Minerals