Chromite, FeCr2O4 (iron chromium oxide), is the most important ore of chromium, from which it derives its name. Chromium is an important metal and has a wide ra — Photo: Darla Sondrol · CC0
Chromite
Also known as: Chrome iron ore.
Iron-chromium oxide of the spinel group — the only commercial ore of chromium, forming dense black octahedra.
Intro adapted from Wikipedia (CC BY-SA).
Chromite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Fe²⁺Cr₂O₄.
It crystallizes in the cubic crystal system (space group Fd3m). It is a member of the Spinel structural group.
Key properties: Mohs hardness 5.5; specific gravity 4.5–4.8; typically black or brown; Brown streak; Metallic to submetallic luster; refractive index 2.12; optically isotropic.
IMA symbol Chr, grandfathered status — known before the IMA’s founding, named in 1845.
A 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.
It is found associated with Olivine, enstatite, plagioclase, serpentine, magnetite, ilmenite, pyrrhotite, pentlandite, ulvospinel.
The name refers to its CHROMium content.
Collections: Metals & Native Elements.