4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
B : Metal: Oxygen = 3:4 and similar B : With only medium-sized cations
Group. Dimorph of Xieite. Chromite-Hercynite Series.
Chromite-Magnesiochromite Series. The iron analogue of Zincochromite, Cochromite, Manganochromite and Magnesiochromite.
The chromium analogue of Hercynite, Coulsonite and Magnetite.
reflected light: gray-white with a brownish tint. Internal
reflections: brownish red.
cumulus mineral in ultramafic portions of layered mafic
igneous rocks; an accessory mineral in alpine-type peridotites;
also detrital. Common in all meteorites, except carbonaceous
chondrites, and in lunar mare basalts.
is a member of the Spinel Group of minerals that also includes Franklinite, Gahnite, Magnesite
among others. Chromite is the most important ore of chromium (Cr)
from which it derives its name.
Chromium is an important metal that has a wide range of industrial uses.
Chromite forms in deep ultra-mafic magmas and is one of the first
minerals to crystallize.
It is also found in metamorphic rocks such as Serpentines.
Gems and specimens of the Serpentine variety
Williamsite often contain inclusions of microcrystals
Chromite has a Mohs hardness of 5.5 and a metallic luster making for very attractive
faceted gems. Some Chromite specimens and gems may be weakly magnetic due to zones of Magnetite composition.
Chromite was named in 1845 by Austrian mineralogist
Ritter von Haidinger (1795-1871) for its chromium content. The
element chromium (Cr)
was discovered and named in 1797 by French pharmacist and chemist
Louis Nicolas Vauquelin (1763-1829) from the Greek word χρώμα (chrōma)
meaning color, because many of its compounds are intensely colored.
The mineral Vauquelinite was named in 1818 by Swedish chemist Jöns Jakob Berzelius
(1779-1848) to honor Vauquelin.
Chromite is cited as being discovered in France in 1845, the species was originally described
and named chromian-säure eisen in 1798 by
P. Meder from samples discovered on the banks of a small
river in the northern Urals of Russia by Mr.
then director of mines for the Northern part of
the Urals. Chromite has been known by several names over time
starting with the original name, chromian-säure
eisen in 1798, then named Eisenchrom also
in 1798, then named fer chromaté aluminé in
1800, then Chromeisenstein in 1832, then Siderochrome
in 1841, then Chromoferrite in 1843 and finally its
current name, Chromite, in 1845.
widespread; from Gassin, Var, France. Large crystals
from Hangha, Sierra Leone. At Tiebaghi, New Caledonia.
As economic deposits in: the Bushveld complex, Transvaal,
South Africa. From the Great Dyke, Zimbabwe. From many
localities in Turkey. At Saranay and elsewhere in the
Ural Mountains, Russia. From the Moa district, northern
Cuba. On Luzon, Philippines. From the Stillwater complex,
Stillwater County, Montana, USA.
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