mineral

Ruby

Corundum (Aluminum Oxide with Chromium traces), Al2O3:Cr

Hardness: 9.0 (Mohs scale); Color: Vibrant red to pinkish-red; Luster: Vitreous to sub-adamantine; Crystal structure: Trigonal/Hexagonal; Cleavage: None (has parting); Specific gravity: 3.97-4.05

Hardness: 9
Color: Vibrant red to pinkish-red
Luster: Vitreous to sub-adamantine

Identified March 24, 2026More mineral →

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Physical properties

Hardness: 9.0 (Mohs scale); Color: Vibrant red to pinkish-red; Luster: Vitreous to sub-adamantine; Crystal structure: Trigonal/Hexagonal; Cleavage: None (has parting); Specific gravity: 3.97-4.05

Formation & geological history

Formed under high heat and pressure in metamorphic rocks like marble or schist, or in igneous rocks. Most gem-quality rubies are found in alluvial deposits or primary deposits within marble hosted environments, often dating back millions of years.

Uses & applications

Primary use is in high-end jewelry (faceted gemstones, cabochons). Industrial uses include lasers, precision bearings in watches, and scientific instruments due to extreme hardness.

Geological facts

The ruby is one of the four precious stones. The most valuable color is known as 'pigeon's blood' red. Historically, rubies were used by ancient warriors for protection. The word 'ruby' comes from the Latin 'ruber' meaning red.

Field identification & locations

Identify in the field by its intense red color and extreme hardness (second only to diamond). High-quality sources include Myanmar (Burma), Mozambique, Thailand, and Sri Lanka. Collectors look for clarity, saturation of color, and minimal inclusions.

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