Some gemstones are manufactured to imitate other gemstones. For example, cubic zirconia is a synthetic diamond simulant composed of zirconium oxide. The imitations copy the look and colour of the real stone but possess neither their chemical nor physical characteristics as well. However, true synthetic gemstones are not necessarily imitation. For example, diamonds, ruby, sapphires and emeralds have been manufactured in labs, which possess very nearly identical chemical and physical characteristics to the genuine article. Synthetic corundums, including ruby and sapphire, are very common and they cost only a fraction of the natural stones. Smaller synthetic diamonds have been manufactured in large quantities as industrial abrasives for many years. Only recently, larger synthetic diamonds of gemstone quality, especially of the coloured variety, have been manufactured.
There are almost 130 species of minerals that have been cut into gems with 50 species in common use. The names can be mentioned as Agate, Alexandrite and other varieties of chrysoberyl, Amethyst, this was originally a `cardinal gem`, but now no longer so, since huge quantities were discovered in Brazil and the price plummeted. The other names are Aquamarine and other varieties of beryl, Chrysocolla, Chrysoprase, Diamond, Emerald, Feldspar or moonstone, Garnet, Hematite, Jade i.e. jadeite and nephrite, Jasper, Kunzite, Lapis lazuli, Malachite, Obsidian, Olivine or Peridot, Opal or Girasol, Pyrite, Quartz and its varieties, such as tiger`s eye, citrine, agate, and amethyst, Ruby, Sapphire, Spinel, Sugilite, Tanzanite and other varieties of zoisite, Topaz, Turquoise, Tourmaline, and Zircon
Some of the minerals that infrequently occur in gem quality form can be mentioned as Andalusite, Axinite, Benitoite, Cassiterite, Clinohumite, Iolite, Kornerupine, Zeolite or Thomsonite. The other artificial or synthetic materials used as gems are as follows. High lead glass, synthetic cubic zirconia, synthetic corundum, synthetic spinel, and synthetic moissanite, etc.
There are also a number of organic materials used as gems. The names can be mentioned as amber, bone, coral, ivory, jet or lignite, mother of pearl, ammolite i.e. from fossils formed from the shells of extinct ammonites, pearl, and tortoiseshell.
Types of Gemstones
Gemstones for Planets
