Black and Salt and Pepper Diamonds

A black diamond is opaque rather than transparent. In a natural black diamond, the colour comes from a great many dark inclusions, such as graphite, packed through the stone. Instead of sparkle, it has a deep, metallic lustre on its polished surface.

Natural black diamonds are uncommon. Most black diamonds sold today owe their colour to treatment, usually heating or irradiation of heavily included stones. A treated black diamond is still a real diamond, but it must be described as treated.

A salt and pepper diamond is a natural diamond with many visible inclusions, black and white, scattered through a translucent grey body. The pattern looks like a sprinkling of salt and pepper, and no two stones are alike.

These diamonds are chosen for their character rather than their clarity grade. Cut in shapes such as hexagon, kite, pear or rose cut, they make engagement rings that feel earthy, quiet and entirely individual.

Both stones sit outside the usual way diamonds are judged. A salt and pepper diamond is heavily included by definition, and a black diamond cannot be graded for clarity at all. A laboratory report is still valuable: it confirms the stone is diamond and states whether its colour is natural or treated.

Beyond that, judge the stone with your own eyes. Look at the pattern, the lustre and the outline, and ask to see it in different light.

Every diamond is 10 on the Mohs scale, so these stones resist scratching as well as any diamond. Their many inclusions, though, can make them more vulnerable to a hard knock, especially where an inclusion reaches the surface or sits near an edge or point.

A bezel or a protective claw setting, and a design without sharp exposed points, keeps a black or salt and pepper diamond safe for daily wear.

Clean these diamonds gently with warm water, a drop of neutral soap and a soft brush. Because of their inclusions, avoid ultrasonic cleaners and steamers unless your jeweller has checked the stone first.