The Enigma: Billion-year-old black diamond sold for £3.16m
The Enigma: Billion-year-old black diamond sold for £3.16m Named The Enigma, the 555.55 carat gem, which weighs about the same as a banana, had been expected to fetch more than £4.4m. There are competing theories about the origins of the stone, including that it was carried to Earth by an asteroid.diamondLINK