Zircon has been used for thousands of years as a popular jewellery gemstone, as it has a high dispersion which is the cause of the 'fire' or sparkle of a gem when faceted. Some Zircons are naturally radioactive, and must be treated in order to stablise them, although it is generally thought that they pose no danger to humans when untreated.
White, Yellow, Red, Blue, Green
Adamantine, Vitreous, Greasy
Australia, China, Madagascar, Myanmar, Sri Lanka, Thailand