gemstone

Diamond

Carbon (C)

Hardness: 10 on Mohs scale (hardest known natural material), Color: Colorless, yellow, brown, blue, pink, green; Luster: Adamantine; Crystal structure: Isometric (cubic); Cleavage: Perfect octahedral cleavage in four directions; Specific gravity: 3.50-3.53

Color: Colorless, yellow, brown, blue, pink, green
Luster: Adamantine

Identified August 2, 2026More gemstone →

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Physical properties

Formation & geological history

Formed under high-pressure and high-temperature conditions (approximately 900 to 1,300 degrees Celsius and 45 to 60 kilobars) in Earth's mantle at depths of 140 to 190 kilometers, brought to the surface via deep-source volcanic eruptions of kimberlite and lamproite magmas, with geological ages ranging from 1 to 3.5 billion years.

Uses & applications

Widely used in fine jewelry and engagement rings due to its exceptional brilliance and fire; extensively used in industry for cutting, grinding, drilling, and polishing tools due to its extreme hardness.

Geological facts

Diamond is the hardest naturally occurring substance on Earth, yet it is made entirely of carbon, the same element found in graphite and charcoal. The word diamond derives from the ancient Greek word 'adamas', meaning invincible or unbreakable.

Field identification & locations

Can be identified in the field or by testing by its extreme hardness (scratches all other minerals), adamantine luster, and high thermal conductivity. Major deposits are found in Russia, Botswana, Canada, South Africa, and Australia.