gemstone

Blue Sapphire

Corundum (Al2O3)

Hardness: 9 on the Mohs scale. Color: Rich blue (due to trace amounts of iron and titanium). Luster: Adamantine to vitreous. Crystal structure: Trigonal. Cleavage: None (exhibits parting). Specific gravity: 3.98-4.10

Hardness: 9 on the Mohs scale
Color: Rich blue (due to trace amounts of iron and titanium)
Luster: Adamantine to vitreous

Identified August 3, 2026More gemstone →

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Physical properties

Formation & geological history

Formed in aluminum-rich, silica-poor metamorphic or igneous rocks such as marble, basalt, and pegmatites, often over millions of years through high-pressure and high-temperature geological processes.

Uses & applications

Primarily used in fine jewelry (rings, necklaces, earrings), high-end watch crystals, scientific instruments, and industrial cutting/abrasive applications due to its extreme hardness.

Geological facts

Sapphire is the September birthstone and one of the most valued precious gemstones. Synthetic sapphires have been manufactured in labs since 1902 for industrial and commercial use.

Field identification & locations

Identified by its deep blue color, extreme hardness (scratches glass and quartz easily), and lack of cleavage. Commonly found in regions like Kashmir, Myanmar (Burma), Sri Lanka, Madagascar, and Australia.