2.2" Yellow Andradite Garnet Cluster - Stanley Butte, Arizona

Andradite is a species of the garnet group, and although not as well known as some other types of garnets such as almandine or pyrope, it is the most lustrous. There are three varieties of andradite which include melanite (black garnets), topazolite (yellow garnets) and demantoid (green garnets). It occurs in skarns developed in contact metamorphosed impure limestones or calcic igneous rocks; in chlorite schists, serpentinites and in alkalic igneous rocks (typically titaniferous).

Garnets are nesosilicates having the general formula X3Y2(SiO4)3. There are many species of garnet which include pyrope, almandine, spessartine, uvarovite, andradite and grossular (varieties of which are hessonite, cinnamon-stone and tsavorite). Garnets are found in a wide variety of colors including red, orange, yellow, green, purple, brown, blue, black, pink, and colorless, with reddish shades being the most common.