Zircon

Overview

Zircon (ZrSiO₄) is one of the oldest minerals on Earth, with individual crystals dated to over 4.4 billion years. It is NOT cubic zirconia (CZ), which is a synthetic material. Natural zircon is a legitimate gemstone with exceptional brilliance, high dispersion (fire), and a range of attractive colours. The ongoing confusion with CZ is zircon's greatest marketing challenge.

Physical Properties

Mohs hardness: 6 to 7.5 (varies with metamictization). Refractive index: 1.810 to 2.024 (the highest of any common gemstone except diamond). Specific gravity: 3.93 to 4.73. Crystal system: tetragonal. Zircon's high refractive index and dispersion (0.038, close to diamond's 0.044) give it exceptional brilliance and fire.

Colour Varieties

Blue zircon: The most popular variety, produced by heating brownish zircon from Cambodia. The resulting medium blue is vivid and clean. Colourless zircon: Once widely used as a diamond substitute before CZ was invented. Still valued by collectors for its fire and brilliance. Golden and honey zircon: Attractive warm colours. Red and cinnamon zircon: Natural colours found in Sri Lanka and Myanmar. Green zircon: Often metamict (radiation-damaged), showing lower hardness and unusual optical properties.

Major Sources

Cambodia (Ratanakiri Province) produces the majority of blue zircon. Sri Lanka yields zircon in a range of natural colours. Myanmar, Tanzania, and Australia also produce gem-quality zircon.

Why Zircon Deserves More Recognition

Zircon's optical properties rival diamond in brilliance and fire. Blue zircon is one of the most visually stunning affordable gemstones available. The ongoing confusion with cubic zirconia has suppressed demand and pricing, making zircon one of the best values in the gemstone market. December birthstone status (alongside tanzanite and turquoise) has helped raise awareness.