mineral

Corundum (Pink Sapphire / Ruby)

Al2O3 (Aluminum Oxide)

AI-generated identification · may be incorrect

Hardness 9 on Mohs scale, Pink color, Adamantine to vitreous luster, Hexagonal crystal system, No true cleavage, Specific gravity 3.95-4.10

Identified June 13, 2026More mineral →

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Physical properties

Hardness 9 on Mohs scale, Pink color, Adamantine to vitreous luster, Hexagonal crystal system, No true cleavage, Specific gravity 3.95-4.10

Formation & geological history

Formed in metamorphic rocks such as marbles or schists and igneous rocks like syenites. These specimens are often millions of years old and crystallize under high pressure and temperature in aluminum-rich environments.

Uses & applications

Used primarily as gemstones in jewelry; synthetic versions are used for industrial abrasives, watch bearings, and laser applications.

Geological facts

Corundum is the second hardest natural mineral known to man. When red, it is called Ruby; all other colors, like this pink specimen, are called Sapphires.

Field identification & locations

Identify by its characteristic hexagonal barrel shape and extreme hardness (will scratch glass easily). Commonly found in alluvial deposits in Madagascar, Sri Lanka, and Myanmar.