Black diamonds are nowadays very valued by designers. Discovered in 1840, in Brazil, they were first used for industry. In the beginning of the 20th century, jewelers started to use this uncommun and mysterious stone. This stone, named Carbonado by Brezilians, has many commun aspects with white diamonds. Nevertheless there are a few differences. Unlike diamonds, carbonados are not a unique crystal but an aggregate of three minerals: graphite, hematite, diamonds and have a porous aspect. As diamonds, carbonados have a hardness of 10 on the Mohs scale but cutting them is more complicated because they don’t have cleavage planes(weaknesses in the structure of the stone). Therefore, cutting black diamonds generates a huge weight loss (up to 50% of the stone’s rough weight).
Origins still unknown
Diamonds crystallized in the earth’s mantle and were brought up to the surface by volcanic eruptions through volcanic rocks, such as kimberlite. However, no kimberlite has been found in black diamonds. Their origins are still unknown, but some gemologists have different theories. The most plausible explanation is that carbonados have an extra terrestrial origin. It has been observed that black diamonds have been formed in an environment with a high level of hydrogen, out of the solar system, thanks to a supernova (star implosion). The carbonado’s luminescence shows that radioactive elements took part in its formation. Today, the main deposits are still in Brazil, but also in the Central African Republic. As any gemstone, carbonados can be treated by heating or irradiation.
The mysterious and bewitching aspect of this stone caught the attention of many designers. Bare paves his Kite earring with black diamonds. Rivka Nahmias uses roughly cut carbonados beads to create a rock but discreet yellow gold bracelet. Alessa Jewelry perfectly mixes black and white diamonds for her Amara pendant. Hoorsenbuhs dares the total black look with the Phantom black gold ring set with black diamonds. Piercing does follow this trend. Maria Tash sublimates the ear with her white gold and black diamond earring.