mineral

Blue Sapphire (Synthetic or Man-made Glass Imitation)

Corundum (Al2O3) if natural; Lead-glass or Spinal if synthetic

Hardness: 9 on Mohs scale (if natural) or 5-6 (if glass). Color: Deep cobalt blue. Luster: Vitreous (glassy). Crystal Structure: Trigonal (hexagonal) if real; amorphous if glass. Specific Gravity: 3.95-4.03.

Hardness: 9 on Mohs scale (if natural) or 5-6 (if glass)
Color: Deep cobalt blue
Luster: Vitreous (glassy)

Identified March 31, 2026More mineral →

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Physical properties

Formation & geological history

Formed in high-pressure metamorphic environments or igneous rocks rich in aluminum and poor in silica. If synthetic, created via the Verneuil flame fusion process developed in the late 19th century.

Uses & applications

Used primarily in fine jewelry (rings, necklaces), high-end watch crystals, aerospace sensors, and high-durability industrial glass.

Geological facts

Natural blue sapphires get their color from iron and titanium trace elements. The 'Star of India' is one of the world's most famous specimens, weighing 563 carats.

Field identification & locations

Identify in the field by checking for unique inclusions (natural silk) under a jeweler's loupe. Natural stones are rarely as perfectly saturated and inclusion-free as mass-produced imitations. Found commonly in Sri Lanka, Madagascar, and Montana, USA.

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