Top 10 Most Expensive Diamonds in the World

Lola Lin

Lola Lin

April 03, 2025

5 min read

What is the most expensive diamond? Diamonds have fascinated humans for centuries with their brilliance, rarity, and mystique. The most expensive diamonds are not just about size—they combine exceptional color, clarity, and historical significance. No matter if you're a gem enthusiast or just curious, these dazzling stones will leave you in awe. In this article, we’ll dig in to the top 10 most expensive diamonds in the world, including their stories, values, and what makes them so special.

Top 10 Most Expensive Diamonds

1. The Koh-i-Noor Diamond

The Koh-i-Noor, meaning 'Mountain of Light,' is arguably the most famous and controversial diamond in history. Originally weighing 793 carats, it was cut down to 105.6 carats to improve its brilliance.

  • Key facts:
    1. Owned by British Crown Jewels since 1850.
    2. Believed to bring bad luck to male owners.
    3. Estimated to be priceless due to its historical significance.

Learn more about the Koh-i-Noor Diamond's history.

Koh-i-Noor Diamond

2. The Cullinan Diamond

Discovered in 1905 in South Africa, the Cullinan Diamond is the largest rough gem-quality diamond ever found, weighing 3,106.75 carats.

  • Key facts:
    1. Cut into 9 major stones, including Cullinan I (530.2 carats).
    2. Part of British Crown Jewels.
    3. Estimated value: $400 million.

Explore the Cullinan Diamond's story.

Pink Star Diamond

3. The Pink Star Diamond

This 59.60-carat fancy vivid pink diamond holds the record for the most expensive diamond ever sold at auction, fetching $71.2 million in 2017.

  • Key facts:
    1. Originally 132.5 carats before cutting.
    2. Internally flawless clarity.
    3. Renamed 'CTF Pink Star' after its sale.

Read about the Pink Star Diamond's journey.

Hope Diamond

4. The Hope Diamond

This 45.52-carat fancy dark grayish-blue diamond is famous for its supposed curse and stunning color.

  • Key facts:
    1. Currently displayed at Smithsonian Museum.
    2. Estimated value: $350 million.
    3. Shows red phosphorescence under UV light.

Discover the Hope Diamond's mysterious past.

Graff Pink Diamond

5. The Graff Pink Diamond

This 24.78-carat fancy intense pink diamond sold for $46 million in 2010, setting a world record at the time.

  • Key facts:
    1. Originally owned by Harry Winston.
    2. Internally flawless clarity.
    3. Recut by Laurence Graff to improve color.

See more about the Graff Pink Diamond.

Oppenheimer Blue Diamond

6. The Oppenheimer Blue Diamond

This 14.62-carat fancy vivid blue diamond sold for $57.5 million in 2016, setting a record for blue diamonds.

  • Key facts:
    1. Named after its previous owner, Sir Philip Oppenheimer.
    2. VS1 clarity.
    3. Rectangular-cut.

Learn about the Oppenheimer Blue Diamond.

Moussaieff Red Diamond

7. The Moussaieff Red Diamond

At just 5.11 carats, this fancy red diamond is one of the rarest and most valuable per carat.

  • Key facts:
    1. Internally flawless.
    2. Triangular brilliant cut.
    3. Valued at over $20 million.

Read more about the Moussaieff Red Diamond.

Centenary Diamond

8. The Centenary Diamond

This 273.85-carat flawless diamond was unveiled at De Beers' centennial celebration in 1988.

  • Key facts:
    1. Modified heart-shaped brilliant cut.
    2. D-color (highest grade).
    3. Current whereabouts unknown.

Discover the Centenary Diamond's story.

Blue Moon of Josephine

9. The Blue Moon of Josephine

This 12.03-carat fancy vivid blue diamond sold for $48.4 million in 2015.

  • Key facts:
    1. Named after buyer's daughter.
    2. Internally flawless.
    3. Cushion-shaped brilliant cut.

See more about the Blue Moon of Josephine.

Sancy Diamond

10. The Sancy Diamond

This 55.23-carat pale yellow diamond has been owned by multiple European royals.

  • Key facts:
    1. Shield-shaped cut.
    2. Currently in Louvre Museum.
    3. Estimated value: $6 million.

Learn about the Sancy Diamond's royal connections.

Final Thoughts

What is the most expensive diamond? While the Koh-i-Noor may be priceless, other diamonds like the Pink Star and Cullinan have fetched staggering prices at auction. These extraordinary gems combine rarity, beauty, and often fascinating histories. No matter if you're dreaming of owning one or just appreciating their beauty, these diamonds represent nature's most spectacular creations. Their value extends far beyond carat weight—each tells a unique story of human fascination with these brilliant stones.