Primarily formed in
pipes, less commonly in
dikes, of deep-seated, igneous origin, composed of
kimberlite or
lamproite, and in alluvial deposits formed by their weathering. In carbonaceous
achondrite and iron meteorites; may be formed by impact (
Anthony et al., 2001—2005). Famous diamonds:
Golden Jubilee, 545.67 carats, the largest polished gem, cut by Gabriel Tolkowsky, now part of the crown jewels of Thailand, resides in Bangkok;
Cullinan I, also known as the Great Star of Africa, it weights 530.2 carats and is mounted in the Sceptre with Cross, part of the Crown Jewels of the United Kingdom;
Koh-i-Noor, currently 105.60 carats, resides with the rest of the crown jewels, too; the
Black Orlov Diamond, also known as the Eye of Brahma Diamond, 67.50 carats.
