Synthetic Spinel

The chemical composition of synthetic spinel is MgAl2O3; the ratio of Al2O3, MgO is generally 2.5:1, it could up to 4:1(The ratio of Al2O3 and MgO in natural spinel is 1:1);It may contain elements such as Fe, Co, and Cr.Common colors of synthetic spinel are:colorless, light to dark blue, light to dark green, red, yellow, purple, dark blue(Imitation lapis lazuli).Mohs hardness: 8.