Zircon occurs in a wide range of colours, but for many years the most popular was the colourless variety, which looks more like diamond than any other natural stone because of its brilliance and dispersion.

The crystal structure of zircon is tetragonal crystal system  The natural color of zircon varies between colorless, yellow-golden, red, brown, and green. Colorless specimens that show gem quality are a popular substitute for diamond; these specimens are also known as "Matura diamond". It is not to be confused with cubic zirconia, a synthetic substance with a completely different chemical composition.

Today the most popular colour is blue zircon, which is considered an alternative birthstone for December. Most blue zircon is of a pastel blue, but some exceptional gems have a bright blue colour. Zircon is also available in green, dark red, yellow, brown, and orange.

Zircon is mined in Cambodia, Sri Lanka, Thailand, Myanmar, Australia, Tanzania and other countries.

Zircon is one of the heaviest gemstones, which means that it will look smaller than other varieties of the same weight. Zircon jewellery should be stored carefully because although it is relatively hard, zircon can suffer from abrasion and the facets can be chipped. Dealers often wrap zircons in individual twists of paper so that they will not knock against each other in a parcel.