What Are the Most Expensive Diamonds Ever Sold at Auction

Diamonds are arguably the most popular gemstone for jewelry, commonly featured in engagement rings, wedding bands, earrings, pendants, and bracelets. Our fascination with them is no mystery—they come in a wide range of shapes, sizes, and colors, and their sparkle is unmatched. But beyond the everyday diamond, there are extraordinary stones that have commanded staggering prices at auction—and they’re definitely worth a closer look.

Before we take a look at some of those record-breaking stones, let’s go through a crash course on diamonds and how they are graded. This will help you appreciate these fine gemstones.

The Four Cs in a Nutshell

When you're picking out a diamond, the Four Cs are your go-to guide: cut, color, clarity, and carat weight. The cut is often considered the most important aspect because it evaluates how the diamond is shaped and angled to catch the light and give off that dazzling sparkle. The perfect proportions will yield the highest cut grade. Color ranges from D (completely colorless) to Z (yellow), but for the average person, the top grades look almost identical. Clarity refers to the imperfections that are (or are not) present in the stone; they're also called inclusions. The highest clarity grade is internally flawless, and very few stones are given this honor. Lastly, carat weight is a measure of how large the diamond is, weight-wise.

Now that you have a basic understanding of how diamonds are valued, here are our picks for the most expensive diamonds ever sold at auction:

1. The Pink Star

Sold for $71.2 million at Sotheby’s Hong Kong, the Pink Star diamond is the most expensive diamond to ever be sold at auction. Mined by De Beers in Africa, this oval shaped fancy vivid pink diamond weighs 59.60 carats and is graded internally flawless. As rough material straight from the mine, the diamond was 132.5 carats and it took over two years to perfect the stone to what it is today. The auction was won by Chow Tai Fook Enterprises, a Hong Kong jeweler, and it remains one of the rarest diamonds in existence.

2. The Oppenheimer Blue 

Sold for $57.5 million at Christie’s Geneva in 2016, the Oppenheimer Blue diamond was named after Sir Philip Oppenheimer, who was a significant individual in the diamond industry. The Blue Oppenheimer is 14.62 carats and is an emerald cut fancy vivid blue diamond. It is currently set in a platinum ring accented by two trapezoid diamonds and is considered one of the most vivid blue diamonds in existence.

3. The Blue Moon of Josephine 

Sold for $48.4 million at Sotheby’s Geneva in 2015, the Blue Moon of Josephine was mined by Petra Diamonds in South Africa. The rough material weighed 29.6 carats before it was cut and polished to the final 12.03 carats it is today. The diamond is a cushion cut and fancy vivid blue color, with a clarity grade of flawless. Purchased by Hong Kong billionaire Joseph Lau, the stone was named after his daughter, Josephine. It joined a collection of other gems he acquired for her, including the Sweet Josephine and the Star of Josephine.

4. The Graff Pink 

Sold for $46.2 million at Sotheby’s Geneva in 2010, the Graff Pink diamond was previously owned by Harry Winston, but purchased by Laurence Graff, a jeweler. The diamond weighs 24.78 carats and is considered a fancy pink diamond and a Type IIa diamond, which essentially means that it is incredibly chemically pure. Once purchased, the stone was re-cut to make it even more brilliant and it is now set in a platinum ring accented by two white diamonds. It is still considered to be one of the most beautiful pink diamonds in existence today. 

5. The Winston Blue

Sold for $23.8 million at Christie’s Geneva in 2014, this fancy vivid blue diamond was purchased by Harry Winston. It weighs 13.22 carats and is pear shaped. It has a clarity grade of internally flawless. This diamond was mined in South Africa and is incredibly rare for its color, size, and shape. 

The world of auction-worthy diamonds is full of wonderful stones, some rare, some very large, but all incredibly beautiful. From the dazzling Pink Star diamond to the stunning Winston Blue, these gems have attracted significant attention. The intense interest from collectors drove their auction prices even higher than expected.

Understanding the Four Cs—cut, color, clarity, and carat weight—helps us appreciate these rare gemstones and their beauty. They are not just symbols of wealth–though they undoubtedly are–they show us what nature is capable of creating. Only time will tell which new diamonds will be discovered and transformed into dazzling stones—ready to capture attention and fetch millions at auction.