Tools used by Garrard jewellers to prepare fine jewellery in the workshop of Garrard's flagship store in Mayfair on April 6, 2011 in London, England. Garrard is the world's oldest jewellers having been founded by George Wickes in 1735 and soon after appointed as goldsmith to the Prince of Wales. For over 160 years Garrard held the title of Crown Jeweller, bestowed by Queen Victoria in 1843, Garrard have served six successive monarchs. They have produced several royal crowns as well as the engagement ring presented to Kate Middleton by Prince William and formerly Princess Diana's engagement ring. (Photo by Oli Scarff/Getty Images)

A Garrard jeweller examines a Garrard sapphire and diamond necklace from the Regal collection in the workshop of their flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

A woman examines emerald, ruby and sapphire rings set in the Garrard Royal Cluster in Garrard's flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

A preparatory model of the Imperial State Crown of India worn in 1911 by King George V stands next to original ledgers dating from 1735 in Garrard's flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

A bunch of various ring sizes hang in the workshop of Garrard's flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

A woman holds a Garrard Spinnel and Diamond Tiara in Garrard jewellers' boutique area of their flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

A Garrard jeweller examines a diamond earring in the workshop of Garrard's flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

An employee of Garrard jewellers works in the boutique area of their flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

A Garrard jeweller prepares fine jewellery in the workshop of Garrard's flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

A Garrard jewellery designer sketches a design for a diamond ring in their flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

The original ledger showing the first order for Garrard jewellers' in 1735 for the Prince of Wales is opened in boutique area of their flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)

A portrait of Queen Elizabeth II hangs in the workshop of Garrard's flagship store in Mayfair on April 6, 2011 in London, England. (Photo by Oli Scarff/Getty Images)