gemstone
Blue Zircon
Zircon (Zirconium Silicate), ZrSiO4
Hardness: 7.5, Color: Bright cyan blue, Luster: Adamantine to vitreous, Crystal Structure: Tetragonal, Cleavage: Indistinct, Specific Gravity: 4.6-4.7, High double refraction (birefringence).
- Hardness
- 7
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Physical properties
Hardness: 7.5, Color: Bright cyan blue, Luster: Adamantine to vitreous, Crystal Structure: Tetragonal, Cleavage: Indistinct, Specific Gravity: 4.6-4.7, High double refraction (birefringence).
Formation & geological history
Formed in igneous and metamorphic rocks; heavy mineral sands. Most blue zircons are heat-treated from reddish-brown crystals found in Cambodia.
Uses & applications
Primarily used as a gemstone in high-end jewelry. Industrially, zircon is a source of zirconium and zirconium dioxide.
Geological facts
Zircon is the oldest mineral on Earth, with some grains dated to 4.4 billion years. It is a traditional birthstone for December.
Field identification & locations
Identify by its high dispersion (fire) and strong double refraction, which causes a doubling of facet edges when viewed through the table. Common in Cambodia, Sri Lanka, and Thailand.
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