Blue Diamond

Physical Properties

Hardness: 10 (Mohs scale), Color: Fancy Deep Blue, Luster: Adamantine, Crystal Structure: Isometric (cubic), Cleavage: Perfect octahedral, Specific Gravity: 3.52

Formation & Geological History

Formed under extreme pressure and heat 100-400 miles deep in the Earth's mantle; some blue diamonds are 'super-deep' stones formed near the lower mantle. Age is typically 1 to 3 billion years.

Uses & Applications

Extremely high-end jewelry, investment commodity, and important geological research specimens.

Geological Facts

The blue color is caused by trace amounts of Boron trapped in the carbon lattice. The Hope Diamond is the most famous example of this mineral variety.

Field Identification & Locations

Identified by its extreme hardness, high refractive index, and unique blue hue. Mostly found in the Cullinan Mine (South Africa) and Argyle Mine (Australia).

Identified on: 5/15/2026

Mode: Standard