gemstone

Black Diamond (Carbonado)

Carbonado (Polycrystalline Diamond)

Hardness: 10 (Mohs); Color: Black or dark grey; Luster: Adamantine to sub-metallic; Crystal structure: Isometric (aggregated); Specific gravity: 3.1-3.3

Hardness: 10 (Mohs)
Color: Black or dark grey
Luster: Adamantine to sub-metallic

Identified July 11, 2026More gemstone →

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Physical properties

Hardness: 10 (Mohs); Color: Black or dark grey; Luster: Adamantine to sub-metallic; Crystal structure: Isometric (aggregated); Specific gravity: 3.1-3.3

Formation & geological history

Found primarily in alluvial deposits in Brazil and the Central African Republic. Hypothesized to have extraterrestrial origins or formed via high-pressure metamorphosis approximately 2.6 to 3.8 billion years ago.

Uses & applications

Extensively used in industrial drilling and cutting tools due to its extreme toughness. High-quality specimens are cut into gemstones for modern jewelry.

Geological facts

Carbonado is more porous than conventional diamond and consists of a random orientation of diamond crystals, making it more resistant to cleavage. Some scientists believe it arrived on Earth via a meteorite.

Field identification & locations

Identified by its extreme hardness and opaque black appearance. In the field, it typically looks like charcoal or vesicular volcanic rock but is much heavier and impossible to scratch.

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