mineral

Diamond

Diamond (pure Carbon, C)

Hardness: 10 (Mohs scale); Color: colorless to faint yellow/brown; Luster: adamantine; Crystal system: isometric (cubic); Cleavage: perfect octahedral; Specific Gravity: 3.52

Hardness: 10 (Mohs scale)
Color: colorless to faint yellow/brown
Luster: adamantine

Identified February 5, 2026More mineral →

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Physical properties

Hardness: 10 (Mohs scale); Color: colorless to faint yellow/brown; Luster: adamantine; Crystal system: isometric (cubic); Cleavage: perfect octahedral; Specific Gravity: 3.52

Formation & geological history

Formed under extreme pressure and heat deep within the Earth's mantle (150-250 km deep). Transported to the surface by deep-origin volcanic eruptions called kimberlite pipes. Most geological specimens are 1 to 3.5 billion years old.

Uses & applications

Primary use in jewelry as a gemstone due to high dispersion (fire). Industrial uses include cutting, grinding, and drilling tools due to extreme hardness. Also used in high-pressure scientific experiments and heat sinks.

Geological facts

Diamond is the hardest known natural substance. The name comes from the Greek 'adamas', meaning invincible. Famous specimens include the Hope Diamond and the Cullinan. It is the birthstone for April.

Field identification & locations

Identify in the field by its adamantine luster, ability to scratch sapphire (corundum), and lack of thermal conductivity (it feels cold). Found in primary kimberlite deposits or secondary alluvial deposits (riverbeds/shores). Collectors look for 'octahedral' crystal shapes in rough specimens.