Diamond (Round Brilliant Cut)

Physical Properties

Hardness: 10 (Mohs scale); Color: Colorless (shows 'fire' or dispersion); Luster: Adamantine; Crystal Structure: Isometric-Hexoctahedral; Cleavage: Octahedral (perfect in four directions); Specific Gravity: 3.52

Formation & Geological History

Formed under extreme pressure and high temperature 90 to 120 miles below the Earth's surface in the mantle. Transported to the surface by kimberlite and lamproite volcanic pipes. Age: most are 1 billion to 3.5 billion years old.

Uses & Applications

Used primarily in high-end jewelry and as an industrial abrasive for cutting, drilling, and grinding due to its extreme hardness.

Geological Facts

Diamond is the hardest naturally occurring substance on Earth. It is a polymorphic form of carbon, sharing the same chemistry as graphite but with a much stronger atomic bond.

Field Identification & Locations

Identify by its ability to scratch all other minerals, its high refractive index (brilliance), and 'fire'. Lab testing for thermal conductivity is often used to distinguish it from cubic zirconia or moissanite.

Identified on: 4/17/2026

Mode: Standard