Some diamonds are so incredibly unique and sought after, that their prices are constantly changing. Very large top quality white diamonds, and color diamonds that are so rare they are hardly ever seen, seem to break their own records year after year. In fact, seven of the ten most expensive diamonds ever sold at auction were colored diamonds.

It really boils down to how much a person is willing to pay, and more often than not it is quite the sum, as seen at many auctions where these stones bring in more than the estimate . Though colored diamonds can be purchased the same way any colorless diamond is purchased, the rarer and more expensive diamonds are auctioned off at exclusive and high-end auction houses and sales. Here are some of the most expensive diamonds ever sold at an auction.

1. The Graff Pink - $46 Million

The rare pink diamond, weighing in at 24.78-carats was sold 60 years ago by Harry Winston and is currently in a private collection. The name Graff Pink comes from the owner, Laurence Graff, who bought the remarkable diamond for a surprising $46 million, despite the estimate of $27 million to $38 million.

2. Wittelsbach-Graff Diamond - $24.3 Million

Once the most expensive diamonds ever to be sold at auction, the Wittelsbach-Graff Diamond. A 31.06-carat Fancy Deep Grayish Blue diamond with an IF clarity and an unusual cut with 82 facets. The blue jewel has a rich history dating back to 1664 when Philip IV of Spain gave it to his daughter in honor of her engagement. Since then it has passed through royalty, been misplaced, recovered, bought by a private collector before finally being sold to Laurence Graff in 2008 for $24.3 million. Mr. Graff had the diamond recut in order to enhance its color. The diamond became 31.06-carats and gained the Fancy Deep Blue Internally Flawless grading.

3. The Chloe Diamond - $16.2 Million

The Chloe Diamond, an 84.37-carat colorless brilliant-cut diamond, was named after the 12-year-old daughter of the Guess Company founder, Georges Marciano, who bought the diamond for a steep $16.2 million. Not only does the Chloe Diamond have the highest grading, it is unusually large, and possesses the difficult brilliant cut. The diamond was purchased at Sotheby’s in Geneva.

4. Heart Shaped Diamond - $12 Million

The heart-shaped diamond that sold for $12 million though it was estimated at $10 million is the most expensive heart-shaped diamond ever to be sold at an auction. The white diamond with the endearing shape was sold at Christie’s Magnificent Jewels Sale.

5. Rare “Vivid Pink” Diamond - $11.7 Million

The rare "Vivid Pink Diamonds," which was sold at a Christie’s Hong Kong auction for $11.7 million, is a 5-carat Vivid Pink GIA VS1 diamond. The cushion-shaped stone was set in a platinum and 18K gold ring, size 5, and flanked on both sides by shield-shaped diamonds. The diamond has been determined as a type IIa pink diamond.

6. Sun-Drop Diamond- $12.36 Million

The Sun-Drop Diamond is a pear-shaped 11.03-carat Fancy Vivid Yellow diamond that sold for the first time at an auction on November 15th 2011. Sold to an anonymous phone bidder, the yellow diamond beauty was sold for an astounding $12.36 million. The stone was discovered in South African in 2010 and is one of the largest colored diamonds to be auctioned.

7. Flawless Blue Diamond - $9 Million

This 7.03-carat blue diamond, which sold for $9 million at the Sotheby’s semi-annual sale in Geneva, is mostly known for its flawlessness. After a mere 15 minutes of bidding, the stone was sold to an anonymous bidder.

8. Rare Blue diamond- $7.9 Million

A rare Fancy Vivid Blue 6.04-carat diamond sold for $7.9 million at Sotheby’s Geneva. The stone, which was purchased by an anonymous bidder, came from the Premier Mine in South Africa.

9. The Shizuka Diamond - $6.21 Million

There are not many diamonds that are larger than the Shizuka diamond. Its size is what accounts for its high price, though it pales in comparison to the prices of colored diamonds. At 101.27 carats, the colorless diamond was auctioned off in May of 2008 at Christie’s Hong Kong jewelry sale, making it the largest of its kind to be auctioned in Asia. The diamond was bough by a private collector, who purchased it for his wife. The stone is shield-shaped, and boasts an F color. The diamond in its rough form weighed 460 carats. After being cut, the gem has 92 facets.

10. Vivid Green Diamond - $3.08 Million

In 2009, a 2.52-carat Vivid Green diamond was sold at Sotheby’s Sale of Jewels in Geneva. The green diamond ring sold for $3.08 million and is the largest green diamond to be sold at auction.

Unusually large and colored diamonds rarely come around, but when they do, they make quite the splash at auction houses worldwide. It is always exciting to watch as the hammer slams down and the winning price is announced. There is never much disappointment. As a new diamond takes the title of “most expensive diamond sold at auction,” the only question that remains is, what diamond will be next?