gemstone

Diamond

Carbon (C)

Mohs hardness of 10 (hardest known natural substance). Colorless to near-colorless with brilliant adamantine luster. Isometric/cubic crystal system. Perfect octahedral cleavage. Specific gravity is approximately 3.52. High refractive index (2.42) creating exceptional fire and sparkle when faceted.

Identified July 23, 2026More gemstone →

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Physical properties

Formation & geological history

Formed under extreme high-pressure, high-temperature conditions deep within the Earth's mantle (100 to 150 miles deep) billions of years ago, and delivered near the surface by deep-source volcanic eruptions via kimberlite or lamproite pipes.

Uses & applications

Primarily used in fine jewelry such as engagement rings, eternity bands, and necklaces. Industrial applications use low-grade diamonds for cutting, grinding, drilling, and polishing tools due to their unmatched hardness.

Geological facts

Diamond is composed of pure elemental carbon arranged in a dense crystal lattice. The word diamond originates from the ancient Greek 'adamas', meaning invincible or unbreakable.

Field identification & locations

Identified by supreme hardness (scratches all other minerals), intense brilliance, adamantine luster, and sharp dispersion of light (fire). Natural deposits are famously located in Russia, Botswana, Canada, Australia, and South Africa.