Giant gems with high prices

A model wears the Pink Star diamond at Sotheby's auction house in London on Oct. 24, 2013. The Pink Star, a 59.60-carat vivid pink diamond, is considered the most valuable diamond ever to be offered at auction. The jewel fetched a world record $83 million in Geneva on Nov. 13, 2013.

A Sotheby's employee displays a fancy deep blue diamond containing 10.48 carats during a press preview in Geneva, Switzerland. The diamond was sold for $10.86 million during a Sotheby's auction sale on Nov. 14, 2012 — a new record at auction for a deep blue diamond.

A Sotheby's employee holds a rare 52.82-carat white diamond ring at Sotheby's auction house on April 12, 2010 in London. The ring sold for $8,553,345 at the Geneva Magnificent Jewels Sale, which took place on May 11, 2010 at Sotheby's in Geneva.

A Sotheby's employee holds the largest D color, flawless, type IIa white oval diamond to come to auction on Sept. 9, 2013 in London. The 118.28-carat stone sold for a record $30.8 million at the Magnificent Jewels and Jadeite sale in Hong Kong on Oct. 7, 2013.

The Annenberg diamond is displayed during a press preview of Christie's fall jewel sale on Oct. 16, 2009 in New York City. The flawless 32.01-carat diamond, mounted as a ring and flanked by two pear-shaped diamonds weighing 1.5 and 1.61 carats, sold for $7.7 million at auction.

An employee poses with a 24.78-carat fancy intense pink diamond at Sotheby's in Geneva November 10, 2010. The diamond, mounted as a ring, fetched $46,158,674 when it was auctioned by Sotheby's as part of its Magnificent Jewels sale in Geneva on Nov. 16, 2010.

A model shows The Orange, a 14.82-carat pear-shaped, vivid orange diamond, during a press preview on Oct. 31, 2013 in Geneva. The largest known orange diamond in the world was auctioned by Christie's in the Swiss city of Geneva on Nov. 12, 2013, where it sold for $36 million.

Josephine Johnson, manager of Rio Tinto's Argyle Pink Diamonds, holds the Argyle Phoenix red diamond, one of the world's rarest gems, during a private viewing at a Sydney hotel on May 17, 2013. The Phoenix, which sold for $2 million in October, is included in the 2013 Argyle Diamond collection, named after Rio Tinto's Argyle diamond mine in Western Australia where they were found.

A 7.59-carat, internally flawless, fancy vivid blue diamond is displayed at Sotheby's auction house in New York on Sept. 4, 2013. The Premier Blue, the world's largest round fancy blue diamond ever graded by the Gemological Institute of America, was expected to sell for as much as $19 million during an auction in Hong Kong in October, but did not find a buyer.

This 12.76-carat pink diamond -- the largest of the rare and precious stones ever found in Australia -- is named the Argyle Pink Jubilee. The rough stone was found at Rio's pink diamond operations in the Kimberley region of Western Australia and takes 10 days to cut and polish in Perth.

A woman holds the highly transparent 19.72-carat rectangular-cut diamond ring by the famed Tiffany jewelry house on April 30, 2004. Part of a collection of jewelry owned by late American tobacco heiress Doris Duke, the ring sold for $1.2 million at Christie's auction house in Rome on June 2.

This rare pink diamond, nicknamed the Princie diamond, sold for $39.3 million to an anonymous buyer at a Christie's auction on April 16, 2013 in New York City. The price for the diamond was the second-highest ever for a jewel sold at auction.

A model displays a 110.03-carat sun-drop diamond described as fancy vivid yellow, the highest color grading by gemstone experts, at a Sotheby's preview show in Geneva, Switzerland. It is the world's largest known yellow diamond and sold at auction for over $10.9 million on Nov. 15, 2001.

A gloved hand holds one of the largest diamonds ever to come up for auction in London's Sotheby's auctioneers on Oct. 7, 2003. It is graded a D color and is internally flawless — making it one of the most valuable types of diamond. Weighing 103.83 carats, it was expected to fetch up to $6 million at auction.

This is the 35-carat, pear-shaped diamond that Marie de Medici wore at her coronation in 1610. It sold for $9.7 million at auction in Geneva on May 15, 2012. The stone, called the Beau de Sancy, gets its name from diamond collector Nicolas Harley de Sancy, who bought it in Constantinople, now Istanbul, in the late 16th century. Passed down through the royal families of France, England, Prussia and the Netherlands, the diamond has witnessed 400 years of European history.