garnet - any of a group of hard glassy minerals (silicates of various metals) used as gemstones and as an abrasive

gem, gemstone, stone - a crystalline rock that can be cut and polished for jewelry; "he had the gem set in a ring for his wife"; "she had jewels made of all the rarest stones"

amethyst - a transparent purple variety of quartz; used as a gemstone

aquamarine - a transparent variety of beryl that is blue green in color

calcedony, chalcedony - a milky or grayish translucent to transparent quartz

chrysolite - a brown or yellow-green olivine found in igneous and metamorphic rocks and used as a gemstone

chrysoprase - a green variety of chalcedony valued as a gemstone

citrine - semiprecious yellow quartz resembling topaz

adamant, diamond - very hard native crystalline carbon valued as a gem

emerald - a green transparent form of beryl; highly valued as a gemstone

kunzite - a pinkish lilac crystal form of the mineral spodumene that is used as a gemstone

moonstone - a transparent or translucent gemstone with a pearly luster; some specimens are orthoclase feldspar and others are plagioclase feldspar

morganite - a kind of pink beryl used as a gemstone

peridot - a pale green variety of chrysolite; used as a gemstone

ruby - a transparent deep red variety of corundum; used as a gemstone and in lasers

water sapphire - a deep blue cordierite often used as a gemstone

sapphire - a precious transparent stone of rich blue corundum valued as a gemstone

hiddenite - a green transparent form of the mineral spodumene used as a gemstone

aventurine, sunstone - a translucent quartz spangled with bits of mica or other minerals

topaz - a mineral (fluosilicate of aluminum) that occurs in crystals of various colors and is used as a gemstone

tourmaline - a mineral that is a complex borosilicate and hydroxide of aluminum containing iron and magnesium and calcium and lithium and sodium; it is usually black but occurs in transparent colored forms that are used as gemstones