Not to be confused with the well-known synthetic diamond simulant cubic zirconia, zircon is a zirconium-containing silicate with a variety of industrial and ornamental applications. The mineral contains small amounts of the radioactive elements thorium and uranium, which slowly break down its crystalline structure over time in a process known as metamictization. This allows zircon crystals to be tested for their age via radiometric dating, with specimens from Western Australia found to be the oldest known minerals on earth.

With a name derived from an ancient Persian for “golden-colored”, zircon has been used as a gemstone since biblical times. Under its previous name of “hyacinth”, it is traditionally associated with reddish, orangish, yellowish and/or brownish hues, while blue is perhaps most commonly encountered today.

Colorless zircon is the most convincing natural diamond simulant, but has now been superseded by the synthetic materials moissanite and the above-mentioned cubic zirconia.