Rock Identifier
Blue sapphire ring (Corundum, Al₂O₃; blue color typically from trace iron and titanium) — gemstone
gemstone

Blue sapphire ring

Corundum, Al₂O₃; blue color typically from trace iron and titanium

AI-generated identification · may be incorrect

Central stone appears oval-cut, deep blue, transparent, and vitreous; Mohs hardness 9, trigonal crystal structure, no cleavage, specific gravity about 4.0. Surrounding colorless stones are likely diamonds or diamond substitutes, set in metal.

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Physical properties

Central stone appears oval-cut, deep blue, transparent, and vitreous; Mohs hardness 9, trigonal crystal structure, no cleavage, specific gravity about 4.0. Surrounding colorless stones are likely diamonds or diamond substitutes, set in metal.

Formation & geological history

Sapphires crystallize in aluminum-rich igneous or metamorphic rocks, commonly basalt, marble, and placer deposits; gem formation spans various geological ages. The pictured stone is cut and mounted jewelry rather than a natural rock specimen.

Uses & applications

Used primarily in jewelry; sapphire is also valued for scratch-resistant watch crystals, scientific windows, and specialized industrial components.

Geological facts

Sapphire is the non-red gem variety of corundum; red corundum is ruby. Heat treatment is common and can improve color and clarity, while “star sapphire” shows asterism from rutile inclusions.

Field identification & locations

Identify by its intense blue color, exceptional hardness, strong brilliance, and refractive index around 1.76–1.77; reliable identification requires gemological testing. Major sources include Sri Lanka, Myanmar, Kashmir, Madagascar, Australia, and Montana.