Alum chromium potassium
Chrome Alum formula KCr (SO4)2 x 12H20. It crystallizes in a regular shape of the crystal as a cube. It crystallizes in the cubic forms of the ordinary. After breaking the wall surface structure is like a seashell. The deep purple color gets its natural origin. This piece was created in the laboratory in Poland. Alum is usually used the tanning of hides and skins in order to, for example, leather gloves