Garnet is a group of related gemstones, the types used in jewelry being: almandine, pyrope, spessartite, grossular, and andradite. The most common, almandine [Fe₃Al₂(SiO₄)₃] and pyrope [Mg₃Al₂(SiO₄)₃] are red or brown. Grossular garnets [] may be red too but also yellow and green, hessionite and tsavorite garnet are both varieties of grossular garnet. Spessartine: Mn₃Al₂(SiO₄)₃ Andradite garnets include the beautiful green demantoid but others in the group may be red, yellow, or black.