The Science Company, NC-6325, Chromium Potassium Sulfate, 100g;

Chromium Potassium Sulfate, also called Chrome Alum, consists of dark, violet-red crystals which are soluble in water. Note: crystals are efflorescent, losing combined water molecules, which results in some hard chunks. Among this chemicals' uses are fixing certain photographic baths, as a mordant in textile dyeing, in ceramic glazes and growing colorful purple crystals.