Garnet

Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. The members share similar physical and crystallographic properties but have a wide range of chemical compositions that define distinct species, which fall into two primary solid solution series, the pyralspite series (pyrope, almandine, spessartine) and the ugrandite series (uvarovite, grossular, andradite). The word comes from the 14th-century Middle English gernet, meaning dark red. In this atlas this entity is the garnet group as a whole, for gemstones recorded only as garnet without a named species; grossular and spessartine have their own entities.