mineral

Ruby (Raw Corundum)

Al2O3 (Aluminum Oxide)

AI-generated identification · may be incorrect

Hardness: 9 on the Mohs scale. Color: Purplish-red to pinkish-red. Luster: Vitreous to sub-adamantine. Crystal Structure: Hexagonal (Trigonal prisms/plates). Cleavage: None (has rhombohedral parting).

Hardness: 9 on the Mohs scale
Color: Purplish-red to pinkish-red
Luster: Vitreous to sub-adamantine

Identified July 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed in aluminum-rich metamorphic rocks like marble or schist, and igneous rocks like syenite. Often found in secondary alluvial deposits (river beds).

Uses & applications

High-value gemstone for jewelry, industrial abrasives, and laser technology (synthetic rubies).

Geological facts

Ruby is the red variety of the mineral corundum; every other color of corundum is called sapphire. It is the second hardest natural mineral known.

Field identification & locations

Identify by its distinct hexagonal crystal shape, high density, and extreme hardness (will scratch almost any other mineral). Often found in Mysore, India or Myanmar.