Almandine and Pyrope are the most widely used Garnet gemstones. Though Almandine is the most common Garnet, it is usually opaque and not fit for gemstone use. Only the less common transparent dark red forms of Almandine are used as gemstones. Pyrope is especially noted for its transparency and frequent lack of flaws or inclusions. A rose-red to violet variety of Pyrope (or intermediary between Almandine and Pyrope) is known as Rhodolite, and is a very well represented in the gem trade.
Spessartite is an orange to orange-red form of Garnet, and has recently increased in popularity, with several new deposits of gem grade material having been recently exploited. Grossular, the most varicolored form of Garnet, has the important gem variety of green Tsavorite, as well as orange-brown Hessonite and a yellow to yellow-green form.
Andradite, the most lustrous of the Garnets, has the rare green Demantoid variety, the yellow Topazolite variety, and the black Melanite variety. Uvarovite, the rarest of the familiar garnets, is seldom found in crystals large enough to be faceted, and is the least represented of all the familiar Garnets.
Color-changing Garnet is an interesting form of this gemstone that has a different color when viewed in natural and incandescent lighting. It can have several color combinations, especially brown or orange in daylight to a pink or light red in incandescent light.