[1] Chromium alum is produced from chromate salts or from ferrochromium alloys.

Alternatively and less commonly, ferrochromium alloys can be dissolved in sulfuric acid and, after precipitation of the ferrous sulfate, the chrome alum crystallizes upon addition of potassium sulfate.

Chromium alum crystallizes in regular octahedra with flattened corners and is very soluble in water.

Aqueous solutions are dark violet and turns green when it is heated above 50 °C.

[3] However, this application is obsolete because the simpler chromium(III) sulfate is preferred.