Kimberlite with Diamond

Physical Properties

Hardness: 6-7 (matrix) / 10 (diamond), Color: Bluish-gray or greenish-gray (‘blue ground’), Luster: Dull to greasy, Crystal structure: Usually brecciated or porphyritic matrix.

Formation & Geological History

Formed deep within the Earth’s mantle (150-450 km) and transported to the surface via rapid, explosive volcanic eruptions called kimberlite pipes. Most are Precambrian to Mesozoic in age.

Uses & Applications

Primary source rock for diamonds; highly valued for diamond mining and geological research on the Earth’s interior.

Geological Facts

Named after Kimberley, South Africa, where a 19th-century diamond rush occurred. Only a small percentage of kimberlite pipes contain enough diamonds to be economically viable for mining.

Field Identification & Locations

Identify in the field by looking for 'blue ground' or 'yellow ground' pipe-like structures. Often contains indicator minerals like pyrope garnet (red) and chrome diopside (bright green).

Identified on: 5/19/2026

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