Among all the precious gemstones in the world, diamonds remain the most admired and highly valued. Their brilliance, durability and cultural symbolism have made them the centerpiece of royal collections, museum displays and record-breaking auctions for centuries. While many diamonds are beautiful, only a very small number are considered truly extraordinary because of their size, color, clarity and history.
The five diamonds below are among the most valuable ever known. Each one is worth enough to buy several luxury mansions, a fleet of exotic cars and still have money left over. From rare pink and blue stones to legendary crown jewels, these diamonds are famous not only for their price but also for the stories attached to them.
Why Are Diamonds the Most Valuable Gemstone?
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Even a high-quality everyday diamond can cost a significant amount, and there is a reason for that. Diamonds themselves are not as rare as many people believe, but gem-quality diamonds are much harder to find. Most diamonds recovered from mines are classified as industrial grade. These stones are usually dull, unattractive or unsuitable for jewelry, so they are used in manufacturing, cutting tools and other industrial applications.
For a diamond to become exceptionally valuable, several factors must come together. Weight, clarity, color and cut all play a major role. These are often known as the four Cs. A large diamond with flawless clarity is already impressive, but when it also has an unusually rare color or a famous history, its value can rise dramatically.
The most expensive diamonds in the world are outstanding examples of nature, craftsmanship and heritage. Some are known for their size, others for their unique color, and a few have become priceless because they are connected to royalty and national treasure collections. The No. 1 diamond on this list is literally a crown jewel.
5. The Pink Star Diamond
Sotheby’s
Estimated worth: $71.2 million
The Pink Star Diamond takes fifth place among the world’s most valuable diamonds. It was mined by De Beers in Africa in 1999, although the exact location of its discovery has not been publicly confirmed. In its rough form, the stone weighed an impressive 132.5 carats.
After two years of careful cutting and polishing by the Steinmetz Group, the diamond was transformed into a magnificent 59.6-carat gemstone. The finished stone was graded internally flawless, making it one of the finest pink diamonds ever discovered.
The Pink Star is recognized as the largest pink diamond in the world. It was first shown to the public in Monaco in 2003, where its vivid color and exceptional clarity attracted immediate attention. However, it was not sold until 2017, when it appeared at a Sotheby’s auction in Hong Kong.
The diamond was purchased by the Hong Kong jewelry company Chow Tai Fook for $71.2 million. That sale made it the most expensive diamond ever sold at auction. After the purchase, the buyer renamed it the CTF Pink Star in honor of the family business and its legacy.
4. The De Beers Centenary Diamond
De Beers Group / Internet Stones
Estimated worth: $90 million
The De Beers Centenary Diamond was discovered in 1986 at the Premier Mine in South Africa. In its rough state, the diamond weighed 599 carats. Two years later, it was officially unveiled during the 100th anniversary celebration of De Beers, which is why it was named the Centenary Diamond.
Cutting such an important stone required extraordinary skill and patience. The rough diamond was eventually shaped into a heart-shaped gemstone weighing 273.85 carats. The finished diamond has 247 facets, giving it remarkable brilliance and depth.
It also received a D color rating, the highest possible grade for a colorless diamond. At the time of its unveiling, the Centenary Diamond was considered the largest known modern-cut diamond with flawless clarity both inside and out.
Although the diamond has never been officially valued for sale, it was insured for $100 million before being placed on public display in the 1990s. Its current ownership and exact location are not publicly known, which adds to the mystery surrounding this remarkable gemstone.
3. The Hope Diamond
Wikimedia
Estimated worth: $200-350 million
The Hope Diamond is one of the most famous blue diamonds in the world. The image above shows it on display at the National Museum of Natural History in 1974. Its deep blue color, long history and legendary reputation have made it one of the most recognizable gemstones ever discovered.
The diamond was originally purchased by the French traveler Jean Baptiste Tavernier. At that time, it reportedly weighed 112 carats and was described as having a deep violet-blue color. It is believed to have come from the Golconda region, which is known for producing some of history’s most celebrated diamonds.
Tavernier later sold the diamond to King Louis XIV of France, who had it set into royal jewelry. In 1792, during a period of political upheaval, the diamond was stolen. It eventually resurfaced, but part of its original tear-shaped form appeared to have been cut away, likely to disguise the stolen stone.
Today, the Hope Diamond weighs about 45 carats. After passing through several owners, it was donated to the Smithsonian Institution in 1958. Since then, the vivid blue diamond has rarely left the museum, making it one of the most important attractions in the Smithsonian’s gem collection.
2. The Cullinan I Diamond
Wikimedia Commons
Estimated worth: $400 million
The Cullinan Diamond was discovered in South Africa in 1905 and remains one of the most important diamond finds in history. In its rough form, it weighed an astonishing 3,106 carats, making it the largest rough diamond ever found at the time. It was named after the chairman of the mine where it was discovered.
The massive stone was later divided into 105 individual diamonds of different shapes and sizes. The most famous of these are the nine major Cullinan diamonds, which together weigh about 1,055 carats.
The largest of them, known as Cullinan I, weighs 530.2 carats. It is also called the Star of Africa and is considered the largest clear-cut diamond known. The stone is mounted in the Sovereign’s Sceptre with Cross and forms part of the British Crown Jewels.
The slightly smaller Cullinan II is known as the Lesser Star of Africa. Like Cullinan I, it is part of the royal collection and is closely associated with British ceremonial regalia. Because of their size, clarity and historic importance, the Cullinan diamonds are among the most valuable gemstones in the world.
1. The Koh-i-Noor Diamond
Cyril Davenport / Wikimedia Commons
Estimated worth: $170-480 million
The Koh-i-Noor Diamond is pictured here in the cross of Queen Mary’s Crown. Its name means “Mountain of Light,” a fitting title for one of the most famous diamonds in history. The stone is valuable not only because of its beauty but also because of its royal associations and complex past.
The Koh-i-Noor originally weighed 793 carats before being cut and polished into a 105.6-carat gemstone. It passed through the hands of several rulers in India before coming under British control during the 1800s. Since then, it has remained part of the British royal collection.
The diamond was later set into the crown of Queen Elizabeth, the Queen Mother. It has not been widely seen in public since 2002, when the crown was placed on top of the Queen Mother’s coffin during her funeral ceremony.
The Koh-i-Noor is also surrounded by legend. Some believe the diamond carries a curse, particularly for men who possess it. Over the centuries, several male owners lost power or died after owning the stone, which helped create its mysterious reputation. Since the mid-1800s, it has traditionally been worn or carried by women.
Because of its history, symbolism and connection to the Crown Jewels, the Koh-i-Noor is almost impossible to value with certainty. Estimates vary widely, but its cultural importance may be even greater than its financial worth. Together with the rest of the British Crown Jewels, it remains one of the most famous gemstone treasures in the world.