Andradite is a member of the Garnet group. It is popular with collectors due to its perfectly symmetrical crystals, particularly in matrix. The transparent green variety, known as Demantoid, is a very rare and desirable gem, with a durable hardness of 7 on the Mohs hardness scale. Other colors include lemon-yellow/yellow-green (Topazolite, named after its similarity to Topaz and rarer than Demantoid), black (Melanite) and brownish yellow and brownish red. It often occurs in association with Albite, Biotite, Calcite, Quartz, Hematite, Diopside and Magnetite to name a few.
The crystal system for Andradite is isometric, primarily forming distinctive dodecahedral crystals and intergrown dodecahedral crystal clusters, occasionally trapezohedral crystals, and even complex combinations of the two. Other forms include granular and massive.
Andradite is found in various locations throughout the world, including Canada, Italy, Mali, Mexico, Namibia, Russia, South Africa and the USA (Arizona, California).