An “extremely rare” black diamond weighing 93 carats has been put on display at London’s Natural History Museum, IDEX Online reports. The polished stone originates from a rough of over 300 carats thought to be discovered in Brazil.
The stone was bought by the lender’s family during the late 1800s in Goa, India. After it was cut and polished, the impressive gem was “set into a white gold pendant with an Arabic-inspired design, including 41 colorless and 26 yellow diamonds on the rear” depicting the Ursa Major constellation.
Robin Hansen, gems curator at the museum, said: “This gemstone appears black because it is made up of tiny individual diamond grains that are intergrown, known as polycrystalline. It also contains many minute inclusions of other minerals, mostly black graphite. The boundaries between the different grains, as well as these inclusions prevent light from passing through the diamond, so although it is partly translucent, it appears opaque black. The inclusions also create a glitter-like effect inside the diamond.”
