Description | Grossular is calcium-aluminum garnet, having ideal composition Ca3Al2Si3O12. Grossular, however, typically contains Fe, Mn and other elements in small amounts, so it comes in a variety of colors. It may be colorless, yellow, orange, green, red, grey or black. Grossular, like all garnets, forms dodechahedral (12 sided) crystals with each face having a rhombohedral shape. This crystal is about 5 cm across. |