Medium quality mechanically processed (rounded) diamond. These stones have a high lustre to satin finish with a varying degree of color with no greens, blacks or dark yellows. Although these diamonds are fully processed, the surface texture of these stones may exhibit some irregularities but are free of any fissures and cracks.

These stones are sometimes referred to as “black diamond” and are an opaque, gray/black cryptocrystalline aggregate of diamond crystals, graphite and amorphous carbon. Carbonados usually occur as relatively large, irregular shaped crystalline structures that are mechanically split into angular shapes and desired sizes. Normally, individual carbonado crystals are sized in the range of 10 stones per carat (SPC) or larger. Bits set with carbonados are particularly well suited for use in drilling softer formations.