mineral

Bort or Carbonado

C - Polycrystalline Diamond

Hardness: 10 (Mohs scale), Color: Dark grey to black, Luster: Adamantine to sub-metallic, Crystal Structure: Cubic, Cleavage: None (in polycrystalline form), Specific Gravity: 3.1-3.5

Identified May 27, 2026More mineral →

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Physical properties

Hardness: 10 (Mohs scale), Color: Dark grey to black, Luster: Adamantine to sub-metallic, Crystal Structure: Cubic, Cleavage: None (in polycrystalline form), Specific Gravity: 3.1-3.5

Formation & geological history

Formed under intense heat and pressure deep within the Earth's mantle or potentially from extraterrestrial impact sources (in the case of Carbonado). Usually billions of years old.

Uses & applications

Industrial abrasives, drill bits for mining, cutting tools, and sometimes as lower-grade gemstones for black diamond jewelry.

Geological facts

Carbonado (black diamond) is one of the toughest forms of natural diamond. It is much more porous than typical gem diamonds and is composed of many tiny crystals grown together.

Field identification & locations

Identify in the field by its extreme hardness (it will scratch any other mineral) and its opaque, dark appearance. Commonly found in alluvial deposits in Brazil and Central Africa.