The minerals chromium nitride and chromium sulfide are only found in meteorites. Chromium minerals with industrial value all belong to the chromium spinel minerals. Chromium minerals with industrial value are common among them:
1. Chromite
Chromite is between ferrous chromite and magnesium chromite. Some people usually refer to ferrous chromite and magnesium chromite as chromite. Chromite is an equiaxed crystal system. The crystals are in the form of fine octahedrons, usually in the form of granular and dense block aggregates. The color is black, with brown streaks, semi-metallic luster, hardness 5.5, specific gravity 4.2~4.8, and weak magnetism. Chromite is a mineral of magmatic origin and is produced in ultrabasic rocks. When the ore-bearing rocks are damaged by weathering, chromite is often transferred into placer deposits. Chromite is the main mineral raw material for chromium refining, and low-quality ore rich in iron can be used as high-grade refractory materials.
2. Chromium-rich spar is also called chromite spinel or aluminochromite. Its morphology, physical properties, origin, occurrence and uses are the same as those of chromite.
3. The morphology, physical properties, origin, occurrence and uses of hard chromium spinel are also the same as those of chromite.
