gemstone

Diamond (or Clear Zircon/Sapphire)

Carbon (C)

Hardness: 10 Mohs. Color: Colorless to faint yellow/brown. Luster: Adamantine. Crystal Structure: Isometric-hexoctahedral. Specific Gravity: 3.51.

Hardness: 10 Mohs
Color: Colorless to faint yellow/brown
Luster: Adamantine

Identified July 6, 2026More gemstone →

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Physical properties

Hardness: 10 Mohs. Color: Colorless to faint yellow/brown. Luster: Adamantine. Crystal Structure: Isometric-hexoctahedral. Specific Gravity: 3.51.

Formation & geological history

Formed under extreme pressure and temperature in the Earth's mantle, approximately 90 to 120 miles deep, and brought to the surface by kimberlite volcanic eruptions.

Uses & applications

Primary use in high-end jewelry (engagement rings, necklaces), industrial abrasives, cutting tools, and thermal insulators for electronics.

Geological facts

Diamonds are the hardest known natural substance. The majority of natural diamonds are between 1 billion and 3.5 billion years old.

Field identification & locations

Field identification of a loose cut stone involves checking for high refractive index (brilliance) and testing for thermal conductivity. It is frequently found in kimberlite pipes or alluvial deposits.