Carbonado Diamond - Natural Fancy Black Diamond

A curious stone often referred to as “black diamond,” carbonado is more accurately described as a polycrystalline or aggregate diamond material of amorphous carbon, graphite, and diamond.

This polycrystalline variety of diamond has greater durability than crystalline diamond and is used primarily in industry. However, in February 2022, Sotheby’s sold a faceted, 555.55-ct carbonado diamond named “Enigma.”

Carbonado resembles charcoal. In fact, its name means “burned” in Portuguese, but what burned it may be truly extraordinary.

An Extraterrestrial Material?
Carbonado might have an extraterrestrial origin, which could account for some of its unusual properties. Unlike crystalline diamonds, carbonados are never found in igneous kimberlite rock formed deep within the Earth. Instead, they occur in alluvial, sedimentary deposits. The micro-diamonds present within carbonado (typically smaller than 20 microns or 20 millionths of a meter) lack traces of minerals found deep in the Earth’s mantle, typical of other diamonds. However, they do possess traces of nitrogen, hydrogen, and osbornite (a mineral otherwise found only in meteors). This suggests they originated in outer space.