The 7.03 carat diamond, from the Cullinan mine in South Africa, is no wider than a penny piece, but it is one of only a handful in the world and is expected to reach somewhere between $5.8 million and $8.5 million (£3.9 million and £5.7 million) when it is sold in Geneva.
Democratic America has no crown jewels. but we've got the next best thing, or maybe a better thing altogether, in the Smithsonian's National Gem Collection, on display in the National Museum of Natural History in a new setting that suits its splendour, the Janet Annenberg Hooker Hall of Geology, Gems and Minerals. The gem collection dates back to 1884, when a curator in the Smithsonian's Division of Mineralogy assembled a modest array of American precious stones for display that year at the New Orleans Exhibition. In the ensuing 116 years, the collection has grown to a dazzling scale and beauty, thanks almost entirely to donors who wanted their jewels to be in the nation's museum.
In the bright light, the diamonds, fixed like pin heads to trace a pyramid shape, give out fireworks of colour. Splashes of daffodil yellow, orange, olive green, lavender blue and purple dazzle the eyes. But when the light goes down, the gemstones seem even more miraculous and mysterious. This time, exposed to ultraviolet light, there is an inner glow that makes the colours dance like fireflies in the glass case at London's Natural History Museum. The Aurora collection of 296 coloured diamonds, with a 267.45 carat weight, has been collected and selected over 25 years by Alan Bronstein, an American dealer and gemologist. It was formerly displayed as the Aurora Pyramid of Hope at the American Museum of Natural History in New York from 1989 to 2005.
Diamond exploration in glaciated terrain differs from precious or base metal exploration in that it uses indicator minerals and boulders, instead of till geochemistry, to detect glacial dispersal from a kimberlite. Kimberlites are small (few hundred meters across), circular point sources. They are relatively soft rocks that have been preferentially eroded by preglacial weathering and glacial scouring to deeper levels than the surrounding bedrock surface and as a consequence are covered by lakes or thick glacial sediments. Discoveries of kimberlite on the Canadian Prairies, in the Northwest Territories and northern Ontario and Quebec have sparked unprecedented levels of diamond exploration in the glaciated Shield terrain of Canada and Finland.
The discovery of a lump of lead in Paris has enabled experts to prove that the Hope Diamond, a star exhibit of the Smithsonian Institution in Washington, is the long-lost centrepiece of the crown jewels of prerevolutionary France. It had long been suspected that the Hope, which was given to the Smithsonian in 1958 by the jeweller Harry Winston, came from the Diamant Bleu that was looted in Paris in 1792, when King Louis XVI and Queen Marie Antoinette were being held prisoner. Now François Farge, the chief mineralogist with the Paris Museum of Natural History, has used technology to prove that it is, indeed, the crudely cut-down heart of the 69-carat diamond originally bought by an adventurer in Hyderabad, India, in the 17th century.
Worlds Scarcest Stones Yet to be Discovered by the Public While it may seem Greek to some, the grandidierite, majorite or painite are just a few of the worlds rarest gemstones. And while some may be considered costly, others are surprisingly affordable thanks to their general anonymity to the public. However, each of these rare gemstones represents an exclusivity that can only be attributed to a handful of gems.
Gem expects to find more large diamonds at Letseng Gem Diamonds believes there are more large stones where its latest 478 carat discovery came from. A size frequency distribution model indicates that large, high quality stones will be found on a regular basis. Gem Diamonds' discovery of a 478 carat, white diamond at its Letseng mine in Lesotho does not come as a great surprise to the company that employs a size frequency distribution model indicating the mine will deliver gems of great size on a regular basis.