mineral

Rough Diamond

Diamond (C)

Hardness: 10 (Mohs scale), Color: Dirty gray/brown with greasy luster, Crystal structure: Isometric (often octahedral or dodecahedral but rounded in alluvial form), Cleavage: Perfect octahedral, Specific Gravity: 3.52.

Identified June 11, 2026More mineral →

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Physical properties

Formation & geological history

Formed under high-pressure, high-temperature conditions in Earth's mantle, approximately 90-120 miles deep. Transported to the surface by kimberlite or lamproite volcanic eruptions. Geological ages range from 1 billion to 3.5 billion years.

Uses & applications

Industrial-grade diamonds (Bort) are used for cutting, drilling, and grinding. Gem-quality specimens are used in jewelry. Small rough specimens are popular with mineral collectors.

Geological facts

Diamonds are the hardest known natural substance. This specific specimen appears to be an industrial-grade or 'fancy' rough stone, showing the characteristic adamantine to greasy luster and rounded, irregular shape typical of unpolished stones.

Field identification & locations

Identify by its extreme hardness (cannot be scratched by anything but another diamond) and high thermal conductivity. Commonly found in kimberlite pipes or alluvial deposits in riverbeds. Look for a greasy coating often seen on rough stones.