gemstone

Diamond

Carbon (C)

Hardness: 10 on the Mohs scale. Color: Typically colorless, but can be yellow, brown, blue, pink, or green. Luster: Adamantine. Crystal Structure: Isometric (cubic). Cleavage: Perfect octahedral cleavage in four directions. Specific Gravity: 3.50-3.53.

Hardness: 10 on the Mohs scale
Luster: Adamantine

Identified July 28, 2026More gemstone →

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Physical properties

Formation & geological history

Formed under high temperature and extreme pressure conditions in Earth's mantle, typically at depths of 140 to 190 kilometers (87 to 118 miles), and brought to the surface by deep-source volcanic eruptions (kimberlite and lamproite pipes). Most natural diamonds are between 1 billion and 3.5 billion years old.

Uses & applications

Widely used in fine jewelry and engagement rings due to its exceptional brilliance and hardness; extensively used in industrial applications such as cutting, drilling, grinding, and polishing tools.

Geological facts

Diamond is the hardest known natural material on Earth. A diamond's exceptional ability to disperse light into its spectral colors is known as 'fire'. Famous large diamonds include the Cullinan Diamond, the largest gem-quality diamond ever found.

Field identification & locations

Identified by its extreme hardness (it will scratch all other minerals), high refractive index, and adamantine luster. Common primary sources include Russia, Botswana, Canada, South Africa, and Australia.