Carbonado diamonds are typically pea-sized or larger porous aggregates of many tiny black crystals.

The most characteristic carbonados are mined in the Central African Republic and in Brazil, in neither place associated with kimberlite, the source of typical gem diamonds.

[3] Carbonado exhibits strong luminescence (photoluminescence and cathodoluminescence) induced by nitrogen and by vacancies existing in the crystal lattice.

[7][8][9] Supporters of an extraterrestrial origin of carbonados such as Stephen Haggerty propose that their material source was a supernova which occurred at least 3.8 billion years ago.

It possibly fragmented during entry into the Earth's atmosphere and impacted in a region which would much later split into Brazil and the Central African Republic, assumed to be the only two known locations of carbonado-diamond deposits.

[2] The largest cut black diamond in the world is a carbonado named 'The Enigma', weighing 555.55 carats (111 g).