What is behind the disruptive spread of black diamonds in jewelry? First of all, the need to broaden the palette offered by gems to fashion designers with an essential chromatic element. Black, relatively new in jewelry, is in fact the color of elegance, sobriety, of classic dress, a must for evening events. The market has also long been chasing gems that can also be worn by a male audience and that have a noble and precious DNA. The time had already come for the popularity of diamonds in colors such as pink, yellow, orange, green and others (whose color is due, when natural, to deformations of the crystalline structure or to the presence of atoms such as boron and nitrogen that replace carbon).

Black diamonds can be natural or, very often, they can have undergone treatment. The fact is that in the last 15 years they have literally taken off in jewelry even of high finish. Natural black diamonds generally polycrystalline (aggregation of millions of small crystals) also owe their color to inclusions of minerals such as magnetite, hematite and native iron and have been used since ancient times. It is precisely the clear network of natural inclusions often emerging that gives them little shine on the surface and causes great difficulty for the cutter. Natural black diamonds have a low yield when cut and therefore have not historically been suitable to satisfy the demand.

The strong market demand then led to the use of very fractured diamonds, with less defined colors. These, after a high temperature and low pressure treatment that leads to the graphitization of the fractures (hence the well-defined black color), constitute the majority of black diamonds on the market. The artificial irradiation treatment is rarer and is more expensive than the previous one, cannot use very cheap rough and often presents greenish zoning. The treated gems will however present themselves with a much better polish and are more suitable for setting.