Diamond in Kimberlite

Physical Properties

Hardness: 10 (diamond), 6-7 (matrix); Color: Dark grey/blue-grey matrix with transparent inclusion; Luster: Adamantine (diamond), Dull/Earthy (matrix); Crystal structure: Isometric (diamond); Specific gravity: 3.51 (diamond).

Formation & Geological History

Formed deep within the Earth's mantle at high pressure and temperature, transported to the surface via explosive volcanic eruptions known as kimberlite pipes. Most are between 1 to 3 billion years old.

Uses & Applications

Primary source of industrial and gem-quality diamonds; used in jewelry, high-end cutting tools, and scientific research.

Geological Facts

Kimberlite is named after Kimberley, South Africa, where the first significant diamond discoveries in this rock type occurred. Only about 1 in 100 kimberlite pipes contains economic quantities of diamonds.

Field Identification & Locations

Identify in the field by looking for dark, heavy, porphyritic ultramafic rocks in crater or pipe structures. Often associated with indicator minerals like pyrope garnet and chrome diopside.

Identified on: 4/25/2026

Mode: Standard