gemstone

Blue Zircon

Zircon (Zirconium Silicate, ZrSiO4)

Hardness: 7.5; Color: Vivid neon blue (heat treated); Luster: Adamantine to vitreous; Crystal structure: Tetragonal; Cleavage: Indistinct; Specific Gravity: 4.6-4.7

Hardness: 7
Color: Vivid neon blue (heat treated)
Luster: Adamantine to vitreous

Identified July 9, 2026More gemstone →

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Physical properties

Hardness: 7.5; Color: Vivid neon blue (heat treated); Luster: Adamantine to vitreous; Crystal structure: Tetragonal; Cleavage: Indistinct; Specific Gravity: 4.6-4.7

Formation & geological history

Zircon is an igneous mineral found as primary grains in granite and pegmatites. The blue variety is typically formed by heat-treating brownish zircon found in sedimentary alluvial deposits, particularly in Southeast Asia.

Uses & applications

Primarily used as a gemstone in high-end jewelry due to its high refractive index and dispersion (fire), which rivals diamond.

Geological facts

Zircon is the oldest mineral on Earth, with some specimens dating back 4.4 billion years. Blue zircon is the most popular color and is a traditional birthstone for December.

Field identification & locations

Identified by its high luster, 'doubling' of facet edges when viewed through the table due to high birefringence, and extreme density. Common locations include Cambodia, Sri Lanka, and Myanmar.