Artificial Colours
Black Diamonds
While the name black diamond may sound exotic, the black colour in diamonds is not fancied by experts. The black colour is caused by a large number of carbon crystal inclusions, which are very similar to coal. The main problem with these diamonds is that their inclusions are so numerous, they make the entire stone somewhat porous and impossible to polish well. Black diamonds will have a metallic luster and a surface full of small pits. They also are at a much higher risk of fracture than white diamonds, for precisely the same reasons. As you will see, numerous inclusion can be dangerous for a diamond's integrity.
However, being much cheaper than white diamonds, black ones are still popular within some parts of the market. They may sometimes be polished into a round cabochon shape, or rose cut, instead of brilliant, since the regular faceted shape of a cut diamond is optimized for translucent stones to show off their brilliance. They are used more often in gentlemen's jewellery, yet there is definitely room for all kinds of creative uses of these unique gems, such as the Spirit of De Grisogono black diamond ring on the left, containing the world's largest, 312 carat black diamond.
