First making a bold statement in contrasting art deco jewellery, Black Diamonds have resurfaced again in the early 2000s made popular once again by companies like De Grisogono.
Black Diamonds derive their colour from numerous graphite platelet inclusions turning them dark, often black and opaque. The colour black is essentially the result of total visible light absorption. The presence of many inclusions and an often irregular structure made up of many minute interlocking crystals makes it challenging to cut and polish black diamonds. Thus a less than adequate finish is unfortunately often seen.
Due to popular demand outpacing fine quality natural supply, neutron irradiated stones have since entered the market in large quantities and have been well received due to the limited inherent value of natural black diamonds. Irradiated black diamonds are actually extremely dark green in colour and are easily separated from their purely natural dark grey counterparts if inspected under strong transmitted light.
Fine black diamonds are always selected for a distinct lack of surface cracks, nicks and pits as well as for an absence of any reflective sub-surface inclusions reminiscent of metal. An even black colour without transparent, colourless or lighter areas and an overall high mirror-like lustre are furthermore essential in top quality.