[3] Cr2O3 has the corundum structure, consisting of a hexagonal close packed array of oxide anions with 2⁄3 of the octahedral holes occupied by chromium.

Cr2O3 occurs naturally as the mineral eskolaite, which is found in chromium-rich tremolite skarns, metaquartzites, and chlorite veins.

[4] The Parisians Pannetier and Binet first prepared the transparent hydrated form of Cr2O3 in 1838 via a secret process, sold as a pigment.

Chromium(III) oxide is a precursor to the magnetic pigment chromium dioxide, by the following reaction:[8] Along with many other oxides, it is used as a compound when polishing (also called stropping) the edges of knives, razors, surfaces of optical devices etc.

Although insoluble in water, it reacts with acid to produce salts of hydrated chromium ions such as [Cr(H2O)6]3+.

When heated with finely divided carbon or aluminium, it is reduced to chromium metal: Unlike the classic thermite reaction involving iron oxides, the chromium oxide thermite creates few or no sparks, smoke or sound, but glows brightly.