It is classified in the ugrandite group alongside the other calcium-bearing garnets andradite and grossular. Ore consists mainly of sphalerite, galena, chalcopyrite, and pyrrhotite in andradite skarn. Associated minerals include nepheline, leucite, titanian andradite, melilite, augite, sanidine, biotite, phlogopite and apatite. Other minerals often associated with hardystonite are franklinite, diopside, andradite garnet, and esperite (fluoresces yellow). Around 2009, there was a significant discovery of demantoid and andradite garnet in Madagascar. Andradite is a species of the garnet group. The mineral in Iron-garnet group is andradite. Andradite is a calcium- and iron-rich garnet.