The average engagement ring diamond weighs 1.7 carats. Now imagine coming across a diamond weighing hundreds, if not thousands of carats more. Diamonds this size are NOT the kind you could wear in a ring or necklace but ARE the size of some of the largest diamonds in the world. No matter where they come from, these discoveries are relatively rare, but they do happen! The discovery of a large diamond brings with it the possibility of wealth for individuals—and in some cases, even for entire nations. Let’s explore some of the biggest diamonds in the world.
1. The Sergio Diamond
Sergio, the largest raw diamond ever found, weighed 3,167 carats and was found in Bahia, Brazil in 1895. Let’s say that one more time and let the weight of it really...sink...in... 3,167 CARATS! That's 1,862 times larger than the average engagement ring diamond. Sergio is a black diamond, officially classified as a rare black carbonado. Unlike their sparkling clear cousins, black carbonado diamonds are a mix of tiny diamond crystals, graphite and amorphous carbon, all fused together. This unique composition makes them strong and porous, different from the single-crystal structure of most diamonds.
While most diamonds unearthed are formed deep within the Earth's mantle, Sergio is believed to have formed as the result of a carbon-containing meteor slamming into Earth, creating the ideal temperature and pressure conditions for diamond formation—and one whose size was absolutely astronomical, too!
2. The Cullinan Diamond
The enormity of this diamond boggles the mind. The world-famous Cullinan Diamond takes the prize as the largest "gem-worthy" diamond ever found, measuring 101.9mm x 63.5mm x 59, similar in size to a large papaya. Discovered in modern-day South Africa in 1905, the colorless Cullinan Diamond weighed an incredible 3,106 carats.
The cutting process, which occurred in 1908, took eight months, resulting in 105 individual diamonds (9 larger and 96 smaller). The two largest, the Cullinan I (530.2 carats) and Cullinan II (317.4 carats), both categorized as D-colorless diamonds, have been part of the British Crown Jewels since King George V ascended the throne in 1910.
3. The Louis Vuitton Sewelo Diamond
The Sewelo Diamond was found in Botswana’s Karowe mine in April 2019, tipping the scales at 1,758 carats. The diamond, whose name means “rare find” in the Setswana language, was swiftly purchased by luxury fashion house Louis Vuitton. This raw diamond has a dark appearance due to a thin exterior layer of black carbon. The diamond, which measures 83mm x 62mm x 46mm, similar in size to a small mango, is estimated by experts to be roughly 2 billion years old.
4. The Lucara Diamond
Speaking of a hard-to-wrap-your-head-around-sized rough diamond, the Lucara diamond's official weight is 1,175 carats. Currently named for the company that discovered it, the Lucara was found in June 2021—also in Botswana’s Karowe mine. It is believed the diamond originated from a 2,000-carat stone, as several other large diamonds were pulled from the same area around the same time. Lucara Diamond Corporation has revealed that the diamond, currently sitting at a measurement of 77mm x 55mm x 33mm, will be cut into a collection of smaller valuable diamonds.
5. The Lesedi La Rona Diamond
Let’s keep the Karowe mine discoveries going, shall we? Discovered in Botswana’s Karowe mine in 2015, Lesedi La Rona started its journey from uncut diamond to one-of-a-kind gem as a 1,109-carat beauty with measurements of 65mm x 56mm x 40mm, similar in size to a fingerling potato. Cut and polished, the resulting Graff Lesedi La Rona (named after its owner, British jeweler Graff) is the world's largest square, emerald-cut diamond at 302.37 carats. This Type IIA diamond, given the highest color rating (D, meaning colorless) and highest clarity, holds the name “Our Light” in Setswana, following a naming contest that was open to all citizens of Botswana.
6. The Jwaneng Diamond
Found in June 2021 in the Jwaneng Mine of Botswana, the Jwaneng Diamond weighs 1,098 carats in its rough, uncut state. It was discovered by Debswana, a partnership between a prominent jewelry company and the government of Botswana, meaning much of the proceeds from the diamond will be used for further development of the nation. With measurements of 73mm x 52mm x 27mm, this small apple-sized diamond is the largest ever pulled from a Debswana-owned mine. Luck must have been on the side of Botswana diamond miners in early June 2021, as the Jwaneng diamond was found just a week after the Lucara diamond (above) was discovered.
7. The Karowe Diamond of 2023
The Karowe mine strikes again! In 2023, Lucara discovered a 1,080-carat rough diamond in Botswana’s Karowe mine. Measuring 82.2mm x 42.8mm x 34.2mm (similar to the small apple-sized Jwaneng Diamond above), the Type IIA Karowe diamond is one of four 1,000+ carat diamonds recovered by Lucara, thanks in part to advancements in diamond mining technology. Larger diamonds have historically been unintentionally crushed by hammering mining techniques. X-ray transmission technology, or XRT, is now used and functions like an airport baggage scanner. It allows miners to detect specific elements underground, such as carbon found in diamonds, and enables miners to recover larger diamonds without crushing them.
8. The Karowe Diamond of 2020
If, at this point, you’re wishing you were the heir to the Karowe Mine in Botswana, you’re not alone! On top of the incredible Karowe-found diamonds already discussed above, a 998-carat diamond was found in the mine in 2020. This Karowe diamond was one of 31 diamonds found in the mine that year that weighed 100+ carats, with 10 of those weighing more than 200 carats. Currently sharing its name with the slightly larger Karowe Diamond (1,080 carats) listed above, this diamond measures 67mm x 49mm x 45 mm, similar in size to a large plum. This diamond presents some weaknesses and will require splitting before being processed into a finished gemstone.
9. The Excelsior Diamond
Once the greatest, the Excelsior Diamond was the largest in the world until 1905, when the Cullinan Diamond was discovered. The Excelsior Diamond was discovered in 1893 at the De Beers mine in Jagersfontein, South Africa, weighing a more-than-respectable 995 carats and measuring 63.5mm x 50.8mm x 25.4 mm. The blue-white diamond was found by a mine worker who was loading a truck. The diamond was eventually cut into 21 smaller stones, ranging from one carat to 70.
10. The Star of Sierra Leone Diamond
The Star of Sierra Leone diamond was discovered on February 14, 1972, in the alluvial mines of Sierra Leone. Alluvian diamonds are diamonds that have been removed, by natural erosion, from their primary source and are deposited elsewhere, such as shorelines, ocean floors or riverbeds. The Star of Sierra Leone is classified as the largest alluvial diamond ever found and the third largest gem-quality rough diamond ever discovered, weighing 968.9 carats. The diamond, measuring 67mm x 49mm x 45 mm, was ultimately cut into 17 stones, 13 of which were flawless.
11. The Lesotho Legend Diamond
The Lesotho Legend, a magnificent 910-carat rough diamond, was unearthed in 2018 from the Letšeng Mine in Lesotho, Southern Africa. This exceptional stone, boasting a perfect D color and a coveted Type IIA composition, ranks as the fifth-largest gem-quality diamond ever discovered. After meticulous planning and cutting, the Lesotho Legend was transformed into a collection of 67 captivating polished diamonds, totaling 441 carats.
12. The Incomparable Diamond
When you’ve found a diamond so exquisite, there’s only one appropriate name for it: the Incomparable Diamond. The finished 407-carat gem is a golden kite-shaped, fancy, deep brownish-yellow diamond graded as flawless. This 890-carat rough diamond was found by a little girl playing in the dirt and stones in the Democratic Republic of Congo (DRC) in Africa. Finishing the diamond took four years of studying and cutting. Experts take their time strategically mapping and planning during the diamond-cutting process, as the slightest mistake can result in shattering the entire diamond. The Incomparable Diamond's 407-carat size resulted from this cut, along with fourteen smaller diamonds.
13. The Constellation Diamond
This celestially-named diamond was found in Botswana in November 2015 at an impressive 812.77 carats. The cutting of this enormous rough diamond resulted in a 313-carat, emerald-cut stone called “The Constellation I '', which claims its fame as the largest D-color (colorless) diamond ever graded by the Gemological Institute of America (GIA). Yet another beautiful stone pulled from the Karowe mine, this diamond was sold for the record-setting amount of $63 million.
14. The Koh-i-Noor Diamond
While the year of discovery is known for the most iconic, large diamonds, it is unknown exactly when the 793-carat Koh-i-Noor diamond (meaning “Mountain of Light") was found. It came from the alluvial mines in India, and the Hindu religion believed that their gods cherished it. This diamond's long history is filled with Indian court battles, a stint as part of the gemstone-encrusted throne of the Indian Islamic Mughal dynasty and finding a home in the British Crown Jewels. The diamond was ceded to Queen Victoria (King Charles III's great-great-great-grandmother) at 191 carats in 1849 as part of the peace treaty. The diamond, which initially had a rose cut, is a D-color (colorless) diamond. It was recut in 1852 into a beautiful, 105.6-carat oval brilliant cut diamond that measures 36mm x 31.9mm x 13.04mm.
15. The Millenium Star Diamond
The lucky “7 7 7” string of numbers is usually reserved for talking about a winning spin on slot machines. But luck struck in 1990 when the 777-carat Millennium Star diamond was found in alluvial deposits in Zaire (now the Democratic Republic of Congo, or DRC). Cutting the stone resulted in a finished 203.04-carat diamond. The cut-and-polished showstopper was introduced to the world in the fall of 1999 as part of a Millennium Jewels collection, just before the turn of the millennium. Diamonds like these are so valuable that a group of individuals staged a Hollywood-worthy heist attempt on the Millennium Jewels collection while they were on display at London's Millennium Dome—complete with a speedboat chase! Fortunately, the London Police thwarted the attempt and the jewels remained in good hands.
You likely won’t be stumbling across a 1,000-carat diamond any time soon. But, if you are the proud owner of valuable diamonds (or jewelry of any kind), consider protecting them with a personal jewelry insurance policy from Jewelers Mutual. Individuals looking for jewelry insurance are often under the misconception that insuring their jewelry through a homeowners insurance policy is the best choice. And while home insurance companies may be experts at insuring homes, you should protect your jewelry with jewelry insurance experts. Check your rate by clicking the button below.