Zircon Stone Guide

Zircon is zirconium silicate. Some zircon crystals from Australia are over 4.4 billion years old, the oldest known materials on the planet. Zircon has a high refractive index and strong dispersion, so it sparkles brightly and shows visible fire. Cubic zirconia, despite the similar name, is a lab-made zirconium oxide used as a cheap diamond imitation.

Blue is the most popular zircon colour, usually heat treated from brown material. Colourless zircon was historically used as a diamond substitute. Honey, golden, red, orange (hyacinth) and green zircon also occur. Zircon often shows visible facet doubling because of strong double refraction.

Zircon is 6 to 7.5 on the Mohs scale, depending on variety. Blue and colourless zircon sit at the higher end. Zircon can be brittle along facet edges and can chip if struck on a corner. Best in protective settings.

Colour saturation and brilliance drive value. For blue zircon, a vivid medium blue with strong life is the most valued. Clarity should be eye-clean. Cut quality matters because zircon's fire is only fully released by a well-cut stone.

Blue zircon is almost always heat treated from brown Cambodian material. The treatment is stable. Other colours are usually untreated. Cambodia and Sri Lanka are the primary sources, with Myanmar, Tanzania, Australia and Vietnam also producing.

Earrings, pendants and protected ring settings. Blue zircon makes a striking, affordable centre stone for rings worn carefully. Colourless zircon is a genuine, ethical diamond alternative with real fire, though hardness limits it to protected settings.

Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners because of the brittleness on facet edges. Protect from sharp impacts. Store separately from harder gems.

Zircon is one of the most underrated affordable fine gemstones. Vivid blue zircon over 3 carats is realistic on a modest budget. Fine red and green zircon are rarer and cost more.