The Magnificent Seven — BIG-TIME Diamonds and Their Stories

Explore the true stories behind seven of the most magnificent diamonds ever discovered!

Diamonds don’t have to be big to be beautiful. In fact, most diamonds are quite…small. But every now and then, a bigger, bolder sort of diamond emerges. As it turns out, there’s often an equally brilliant background behind these special stones. Here’s a closer look at seven of the all-timers, brought to you by Zillion.

Pictured above are 9 largest polished diamonds cut from the original Cullinan diamond.
Image: Royal Asscher Archives / Image taken by Reena Ahluwalia

The Cullinan Diamond

It’s good to be the chairman of a diamond mine. In 1905 South Africa, it was very, very good to be Sir Thomas Cullinan. On January 26 of that year, a 3,106-carat (or around 1.37-pound) diamond was discovered in his Premier No. 2 mine — and promptly named after him. The massive diamond was then gifted to King Edward VII of the United Kingdom and taken to Amsterdam to be cut. Today, the diamond consists of nine large stones and ninety-six smaller stones — with two of the largest stones forming part of the Crown Jewels. The Cullinan Diamond is also often referred to as “The Great Star of Africa.” It’s easy to see why.

The Excelsior Diamond

Hailed as second-in-line amongst the largest diamonds ever discovered in Africa, the royally named Excelsior Diamond was excavated from the Jagersfontein Mine in South Africa in 1893 — discovered in a dirt pile by a miner, who took it directly to the manager, then left on a handsome new horse, bridle and saddle as a reward. From then until the Cullinan Diamond discovery in 1905, the Excelsior Diamond reigned as the largest known diamond in the world. Today, the beautiful blue-white-tinted diamond weighs slightly over 995.2 carats.

The Millennium Star Diamond

It’s not nearly the size of, say, the Millennium Falcon. But you might say it was once larger than a 747 — carats, that is. The Millennium Star Diamond soared in at 777 carats when it was discovered in alluvial deposits in the Mbuji-Mayi district of the Democratic Republic of Congo (then known as Zaire) in 1990. Clocking in today at 203.04 carats, the Millennium Star Diamond ranks as the world’s second-largest known top-color (Grade D), internally and externally flawless, pear-shaped diamond. It’s owned by the De Beers Group, who insured it for a cool 100 million pounds. The Millennium Star Diamond also survived an attempted jewel heist at London’s Millennium Dome in 2000. You can read more about the foiled heist in crime journalist Kris Hollington’s book Diamond Geezers.

The Incomparable Diamond

The Incomparable Diamond certainly possesses an incomparable backstory. It’s also undergone an extensive “downsizing” and changed ownership at a rapid rate since it was first found by a young girl in the Democratic Republic of Congo (then known as Zaire) in 1989. After discovering the 890-carat diamond in a trash heap near her home (yes, really!), the girl handed it off to her uncle, who sold it to a local diamond dealer…who sold it to Lebanese buyers. The diamond was then shipped to the Belgian city of Antwerp, where a De Beers buyer purchased it, and master diamond craftsmen spent four years forming and refining it into the yellow-brown, shield-shaped step cut, 407.48-carat diamond we see today. The Incomparable Diamond boasts the maximum clarity grade of Internally Flawless (IF) and ultimately ended up in the ownership of Dallas, Texas-based Zale Corporation. After unveiling the diamond as part of its 75th anniversary celebration in 1984, Zales displayed it in the Natural History wing of the Smithsonian Institute in Washington, D.C.

The Sergio Diamond

Technically, this is the world’s largest known diamond. A huge, solid, black carbonado diamond, the Sergio Diamond outweighs the clear Cullinan Diamond, clocking in at a staggering 3,167 carats (or 633.4 grams). This extremely rare and beautiful black diamond was unearthed in Bahai, Brazil in 1895. Many people have attempted to place an accepted monetary value on the Sergio diamond over the years, but it’s remained a truly rare and “priceless” gem. Also up for debate? The Sergio Diamond’s exact origins. Many believe that carbonado diamonds are the result of ancient meteors that embedded in the earth’s crust — while other theories involve their formation in space following a supernova explosion. One thing’s for sure: this is one special (and rather alien) diamond.

The Star of Sierra Leone Diamond

Talk about a sweet story. The Star of Sierra Leone Diamond was discovered on Valentine’s Day of 1972, in a river near an alluvial mine in Koidu, Sierra Leone. At the time of its discovery, this one-of-a-kind diamond weighed just under 968.9 carats. Towards the end of 1972, the Star of Sierra Leone Diamond was purchased by New York City jeweller Harry Winston for $2.5 million. Initially cut into an emerald-shaped stone weighing 143.2 carats, it was later re-cut into 17 separate finished diamonds — of which 13 were deemed flawless. Six of the diamonds cut from the original were later set by Winston into the “Star of Sierra Leone” brooch. Today, the Star of Sierra Leone Diamond remains the fourth-largest gem-quality diamond on record — and the largest alluvial diamond ever discovered. It also possesses perfect chemical purity and is ranked as an extremely rare Type IIa diamond (a category held by less than 1% of all diamonds).

The Golden Jubilee Diamond

In a word, the Golden Jubilee Diamond is…blessed. Regarded as the world’s largest faceted diamond and weighing in at 545.67 carats, this dynamic, fancy yellow-brown gemstone was discovered in 1985 in the same South African mine that produced the Cullinan Diamond 80 years earlier — and soon given a Vatican blessing by Pope John Paul II. In 1997, after a few years of cutting and polishing, the diamond was transported to Thailand, where a group of Thai businessmen fronted by lead purchaser Henry Ho presented it to the King of Thailand during the 50th anniversary of his coronation — hence, the Golden Jubilee name (under De Beers ownership, it was referred to as Unnamed Brown). The world’s largest finished diamond is still owned by the Royal Family of Thailand today, and is displayed as part of the crown jewels within Bangkok’s Royal Museum at Pimammek Golden Temple Throne Hall. In addition to the Pope’s blessing, the Golden Jubilee Diamond has also been blessed by the Buddhist Supreme Patriarch of Thailand and the Islamic Chularatchamontri.

Here at Zillion, size doesn’t really matter. We believe that any diamond is a special stone — and more than worthy of insuring with us (as long as it’s set in a ring, earring, pendant or bracelet). In fact, we implore you to please insure any and all diamond jewelry you might own, regardless of size. Even if it’s not with us. It’s simply not worth losing out on such an amazing investment.


Zillion partners with jewelers to offer their customers lower rates on jewelry insurance. If you don’t see your jeweler on our list, we’re sorry, we won’t be able to offer you a quote for insurance. If you purchased from a Preferred Jewelers International retailer please email us at and let us know the name of the retailer. Thank you.