The name garnet comes from the Latin word ‘granatus’ meaning ‘seeds’ – clusters of garnet crystals resemble the red seeds inside a pomegranate. However, garnets are a set of closely related minerals that form a group, resulting in gemstones of almost every colour. The name garnet refers to this group of minerals related in composition and crystal structure, but with interchangeable elements.
There are more than 20 garnet categories, called species, but only five are commercially important as gems. Those five are pyrope, almandine, spessartine, grossular (grossularite) and andradite. Garnet is rarely pure as many are a mixture of the species.