mineral

Blue Zircon

Zirconium Silicate (ZrSiO4)

Hardness: 7.5 (Mohs scale), Color: Vivid blue to cyan, Luster: Adamantine (diamond-like), Crystal structure: Tetragonal, Cleavage: Indistinct, Specific gravity: 4.6–4.7

Hardness: 7

Identified April 27, 2026More mineral →

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Physical properties

Hardness: 7.5 (Mohs scale), Color: Vivid blue to cyan, Luster: Adamantine (diamond-like), Crystal structure: Tetragonal, Cleavage: Indistinct, Specific gravity: 4.6–4.7

Formation & geological history

Zircon forms as a primary mineral in igneous rocks like granite and pegmatite. Blue zircon is specifically produced through the heat treatment of naturally occurring brown zircon specimens, often found in alluvial deposits dating back millions of years.

Uses & applications

Primarily used as a gemstone in high-end jewelry (rings, pendants) due to its exceptional fire and brilliance. Also used as an industrial source of zirconium and a geochronological tool for dating the Earth's crust.

Geological facts

Zircon is the oldest mineral on Earth, with some specimens dated to 4.4 billion years old. Blue zircon was a favorite during the Victorian era and is the birthstone for December.

Field identification & locations

Identify by its high refractive index and noticeable double refraction (facet edges will appear doubled when viewed through the stone). Commonly found in Cambodia, Sri Lanka, and Myanmar. Use a loupe to check for 'doubling' and internal inclusions.