Diamonds are forever... Diamonds are a girl's best friend... Whatever cliche you want to use, the fact is the world loves diamonds. This incredibly hard and beautifully sparkling type of precious stone has been a coveted item for centuries. An estimated $13 billion worth of rough diamonds are taken out of the ground each year, the majority weighing just a few carats (1 carat = 0.007055 oz). But every now and again, a monster diamond is found, big enough to amaze the exhausted miners who find it, and when eventually cut into a diamond gemstone, these are grandiose enough to impress even the wealthiest of the world's royalty.
This list of the 10 largest uncut rough diamonds will no doubt evolve in coming years, as the diamond industry is huge - and unsurprisingly, worth a fortune. Ten million people worldwide work in this industry with a value of $72 billion a year. As recently as 2013 two huge rough diamonds were found at the Karowe mine in Botswana, Southern Africa, both coming in at over 200 carats each (1.4 oz). And yet neither of these diamonds makes the top 20, never mind the top 10.
Some of these diamonds have become famous, with fascinating histories behind them. The diamonds in the top two positions on our list are vastly different, but are so massive that the chances of finding their equals are infinitesimally small. That is, unless NASA ever decides to take a mining crew to the prosaically-named planet PSR J1719-1438 b, which has a mass greater than the sun, and is believed to be composed mostly of crystalline carbon - better known to the layperson as diamond. Fortunately for the mining companies worried about cheap space gems, this diamond planet is about 3,900 light years (around 23,000 trillion miles) away!
10 The Jonker: 726 carats
This giant gem, found in South Africa in 1934, was found by a settler called Johannes Jacobus Jonker, hence its unusual moniker. It's believed the rough diamond was eventually cut into 13 smaller gemstones, with the largest diamond, the Jonker I, still weighing in at an incredible 142.9 carats. Diamonds are valued by weight, color, clarity and various other factors. However, with a colorless flawless diamond valued at $26,125 per carat, the Jonker I could be worth as much as $3.7 million!
9 The Vargas: 726.6 carats
Beating the Jonker by a whisper is this Brazilian diamond discovered in 1938. This one was named for Getúlio Dornelles Vargas, who was the President of Brazil at the time. The diamond eventually found its way to Amsterdam and was finally bought by someone not only famous in jewelry circles, but who has also become synonymous with the industry as a whole: American jeweler, Harry Winston. Twenty-nine smaller stones were cut from this rock, with the largest being a flawless 44.17 carat gem which had been re-cut by Winston himself.
8 The Golden Jubilee: 755 carats
Extracted in South Africa in 1985, this beauty was actually given a papal blessing from Pope John Paul II after it had been cut and polished. Diamond specialists worked for years on this rough diamond, managing to eventually produce a cut and faceted diamond that weighed an enormous 545.67 carats, making it the largest finished diamond in the world. It is currently owned by the Royal Family of Thailand. At $26,125 a carat, this incredible diamond could be worth over $14 million if it had been colorless. However, as it is a yellow-brown color, it is "only" valued at $4-$12 million.
7 The Woyie River: 770 carats
Named after the river it was found in, this rock from the famous African diamond-producing nation of Sierra Leone was announced in 1945. Eventually the rough diamond was cut into thirty smaller pieces, wielding colorless and flawless gemstones. These stunning diamonds may be questionable, however, for those concerned with human rights: Sierra Leone is famous for blood diamonds; diamonds that have been mined in areas considered war zones and then sold on to help finance further military activity (usually anti-establishment guerrilla warfare).
6 Millennium Star: 777 carats
This large rough diamond was found in the Democratic Republic of Congo in 1990. An estimated 65% of the world's diamonds come from African nations, and this nation yielded an astonishing cut diamond weighing 203.04 carats. This makes it the second largest colorless and flawless diamond in the world (with the highest purity rating of D; the scale goes from D to Z). It is currently owned by the De Beers Group, a diamond industry controlling company which was founded by the British mining explorer Cecil Rhodes. At carat weight alone, the final cut diamond would be worth at least $5 million. But because of its fame, purity and its irreplaceable nature, this gem has been valued at over $160 million.
5 Incomparable Diamond: 890 carats
At 890 carats (just over 6 oz) this Congolese rough diamond was discovered by a young girl in 1989. The smart child noticed the diamond in a pile of rubble and passed it on to her uncle, who sold it to diamond dealers. Like many of the world's diamonds, it ended up at one point in the Belgian city of Antwerp, famous for its diamond district. It took experts years to cut the rough diamond into smaller gems, but they managed to create a beautiful yellow-brown stone weighing 407.48 carats that had been cut into an unusual triangular shape. Strangely enough, this fantastic gemstone actually appeared on eBay in 2002, but went unsold.
4 Star of Sierra Leone: 969 carats
A 1972 discovery, this uncut diamond was purchased the same year by the celebrated American jeweler Harry Winston. The rough diamond was cut and produced 17 smaller almost-perfect diamonds. Some of the smaller gems were placed into a piece of exquisitely-crafted jewelry that became known as the Star of Sierra Leone brooch.
3 Excelsior Diamond: 995.20 carats
Found in 1893 in South Africa, this huge rock was cut into many smaller pieces. The largest gemstone cut from this famous diamond was only 69.68 carats, but many in the diamond industry believe that much larger diamonds could have been taken from the original stone. Intriguingly, another diamond of a similar weight (around 1,000 carats) could have been included in this list, but little is known about it: It's a rare black diamond that has been called The Nameless. No-one seems to know where it came from or when it was discovered, so - for now - it remains a side-note.
2 Cullinan Diamond: 3106.75 carats
Weighing more than three times the weight of the Excelsior Diamond, this is arguably the most famous diamond in the world. It weighed 1.37 lb when discovered by a mining superintendent in South Africa, in 1905, and was named after the owner of the mine, Sir Thomas Cullinan. It was given as a gift to the King of the United Kingdom (Edward VII) and was taken to Amsterdam to be cut. Nine large stones and 96 stones were taken from the rough diamond, including the famous Star of Africa (Cullinan I) which is 530.2 carats and is now part of the Crown Jewels, inserted into the Sceptre with the Cross. The value of the Cullinan diamond has been estimated at $2 billion.
1 "Sergio": 3167 carats
Many still place the Cullinan as the largest rough diamond ever found, with The Golden Jubilee and Star of Africa as the first and second largest polished diamonds in the world respectively. However, "Sergio", a black carbonado diamond from Brazil discovered in 1893, beats all its rivals for weight. These so-called black diamonds are rare and scientists are still in debate over their origins. There are some that believe these black diamonds come from outer space, having travelled to Earth as fragments of an ancient meteor.