mineral

Rough Blue Diamond

Carbon (C)

Hardness: 10 Mohs; Color: Blue (due to Boron impurities); Luster: Adamantine (in cut form) to Greasy (rough); Crystal system: Isometric-Hexoctahedral; Specific gravity: 3.51

Hardness: 10 Mohs
Color: Blue (due to Boron impurities)
Luster: Adamantine (in cut form) to Greasy (rough)

Identified June 11, 2026More mineral →

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Physical properties

Hardness: 10 Mohs; Color: Blue (due to Boron impurities); Luster: Adamantine (in cut form) to Greasy (rough); Crystal system: Isometric-Hexoctahedral; Specific gravity: 3.51

Formation & geological history

Formed under extreme pressure and temperature conditions in the Earth's mantle (150-250km deep) billions of years ago. Transported to the surface via deep-source volcanic eruptions called Kimberlites.

Uses & applications

Extremely rare and valued as a gemstone for high-end jewelry; industrial uses for cutting and grinding (though blue specimens are usually reserved for gems).

Geological facts

Blue diamonds are among the rarest diamonds in the world. The Hope Diamond is the most famous example of a blue diamond, currently housed at the Smithsonian.

Field identification & locations

Identified by high hardness (scratching any other material), crystal habit (octahedral or dodecahedral variants), and oily surface luster in the rough. Primarily found in the Cullinan Mine in South Africa and the Argyle mine in Australia.