mineral

Rough Blue Diamond

Carbon (C) - Type IIb Diamond

Hardness: 10 (Mohs scale); Color: Grayish-blue to deep blue; Luster: Adamantine to sub-metallic in rough; Crystal Structure: Isometric (cubic); Specific Gravity: 3.51

Hardness: 10 (Mohs scale)
Color: Grayish-blue to deep blue
Luster: Adamantine to sub-metallic in rough

Identified June 9, 2026More mineral →

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Physical properties

Hardness: 10 (Mohs scale); Color: Grayish-blue to deep blue; Luster: Adamantine to sub-metallic in rough; Crystal Structure: Isometric (cubic); Specific Gravity: 3.51

Formation & geological history

Formed under extreme pressure and temperature in the Earth's mantle (100-500 miles deep) billions of years ago. Blue diamonds get their color from boron atoms trapped in the carbon lattice.

Uses & applications

High-value gemstones for jewelry, investment pieces, and scientific research into semiconductors. Industrial grades are used for high-precision cutting tools.

Geological facts

Famous blue diamonds include the Hope Diamond. Natural blue diamonds are among the rarest gemstones in the world, representing less than 0.1% of all diamonds mined.

Field identification & locations

Identify by its extreme hardness (cannot be scratched by any other mineral) and adamantine luster when cleaned. Commonly found in kimberlite pipes, notably the Cullinan Mine in South Africa.