Types of garnet

The major types of garnets include: Almandine, Pyrope (also called Bohemian garnet, or Cape ruby), Spessartine, Grossular (also called grossularite, or Gooseberry garnet), Andradite, Rhodolite, Carbuncle, Hessonite (also called essonite, or Cinnamon stone), Topazolite, Uvarovite and Uralian emerald (or demantoid). Here we’ll introduce some of the main types of garnet.
Almandine, sometimes incorrectly called almandite, is the modern gem known as carbuncle. Chemically, almandine is an iron-aluminium garnet with the formula Fe3Al2(SiO4)3. Almandine has nicknames of Oriental garnet, almandine ruby, and carbuncle.
Pyrope is red in color and chemically a magnesium aluminium silicate with the formula Mg3Al2(SiO4)3, though the magnesium can be replaced in part by calcium and ferrous iron. The color of pyrope varies from deep red to almost black.
Andradite is a calcium-iron garnet, Ca3Fe2(SiO4)3, is of variable composition and may be red, yellow, brown, green or black. Andradite is found both in deep-seated igneous rocks like syenite as well as serpentines, schists, and crystalline limestone.
Grossular is a calcium-aluminium garnet with the formula Ca3Al2(SiO4)3, though the calcium may in part be replaced by ferrous iron and the aluminium by ferric iron.
Uvarovite is a calcium chromium garnet with the formula Ca3Cr2(SiO4)3. This is a rather rare garnet, bright green in color, usually found as small crystals associated with chromite in peridotite, serpentinite, and kimberlites.
Spessartite is manganese aluminium garnet, Mn3Al2(SiO4)3. It's name is derived from Spessart in Bavaria. It occurs most often in granite pegmatite and allied rock types and in certain low grade metamorphic phyllites. Spessartite of a beautiful orange-yellow is found in Madagascar. Violet-red spessartites are found in rhyolites in Colorado and Maine.