Natural Red Rhodolite Garnet Faceted 3D Cube Box Length is 4.5 Inches & Sizes from 5mm Approx. Garnets /???rn?t/ are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. Garnets /???rn?t/ are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. The different species are pyrope, almandine, spessartine, grossular (varieties of which are hessonite or cinnamon-stone and tsavorite), uvarovite and andradite.