the square of the weight is multiplied by the price of a single carat; so that, for example, a rough stone of three carats costs 3x3x 2 or 18. It is similar with : cut diamonds, and in 1850 the ...

A rare 102-carat white diamond has sold at auction for $15.7m (£12.1m) in what experts say is a "bargain". The gemstone went to an unnamed telephone bidder. The auction was held online by Sotheby ...

Fancy colored diamonds, colored gems and signed jewels will be featured at New York auctions from Phillips and Bonhams in ...