A massive diamond among the largest ever discovered was recently unearthed in Angola, mining company Lucapa announced Monday. 
 
 At 404.2 carats, it measures about 7 cm across -- about the length of a credit card, Lucapa said. 
 
 It was mined by the Lulo Diamond Project, a partnership between Endiama, Angola's national diamond company, Lucapa Diamond Company, and a private investor, Rosas & Pétalas. 
 
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 New York-based diamond retailer Yehuda tested the new diamond's color and clarity, according to Lucapa, and categorized it as a Type IIa stone -- meaning it's virtually flawless. 
 
 It's also D-colored, or entirely colorless, Lucapa said. That is the rarest -- and likely most valuable -- color grade for a white diamond, according to the Gemological Institute of America. 
 
 The Lulo Diamond Project began exploring a 1,148 square-mile plot of land in central Angola in 2015, and the area has so far produced more than 60 "large special diamonds," the company said. 
 
 Lucapa, a relatively tiny diamond exploration company, is traded on Australia's ASX stock exchange under the symbol LOM. It suspended trading a few days in advance of the announcement. When Lucapa resumed trading on Monday, its shares jumped 30%. 
 
 Chairman Miles Kennedy told ABC Australia that the historical find could be worth about $20 million. 
 
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 Angola is the world's fourth biggest country for diamond production. The 404.2 carat gem is now the largest to ever come out of the country, topping the 217.4 carat gem found in 2007 and dubbed the "Angolan Star." 
 
 The world record was a 3,106 carat gem, called the "Cullinan." It weighed in at a massive 1.3 pounds and was discovered in South Africa in 1905. That stone was cut to adorn the royal sceptor, one of Britian's crown jewels, and is on display at the Tower of London. 
 
 "Cullinan" was nearly triple the size of the second largest diamond on record, which weighed 1,111 carats and was found in November 2014. 
 
 The diamond discovery announced Monday would make it the 27th largest diamond ever recorded. 
 
 --CNN's Justin Lear contributed to this report 

 The diamond is estimated to be worth more than $20 million. 
 
 A Perth-based company has struck paydirt in Southern Africa, finding a diamond worth more than $20 million. 
 
 Lucapa Diamond Company found the massive 404-carat diamond at its Lulo Diamond Project in Angola's Lunda Norte province, in the country's north-east. 
 
 It is the biggest diamond ever found in Angola. 
 
 Lucapa chairman Miles Kennedy said it was a huge achievement. 
 
 "When we first looked at the property, 3,000 square kilometres of untouched ground, 700 kilometres inland from the coast, you are talking about a very, very remote area," he said. 
 
 "The results today are a wonderful vindication of eight years of pretty hard work. 
 
 "It's the biggest diamond ever recorded from the country of Angola and it's the biggest diamond ever recovered by an Australian diamond miner. 
 
 "So, we have hit a number of firsts finding this diamond." 
 
 He said the "spectacular" white diamond, which was considered to be of excellent quality, could be valued at more than $20 million. 
 
 "We're not used to valuing 400-carat diamonds, but if we look at other diamonds slightly less weight than this, you're looking in the order of $20 million," Mr Kennedy said. 
 
 Mr Kennedy has a long history of searching for diamonds, having set up the Ellendale diamond mine in Western Australia's Kimberley in the early 1990s. 
 
 He took his geology team from the Ellendale mine to Angola when he set up Lucapa. 
 
 "I started the Ellendale diamond mine and was there from 1993 to 2007, so 14 years, and in that time we only got one diamond greater than 10.8 carats, known as a special diamond," Mr Kennedy said. 
 
 "With this company in Angola, we have now found over 100 of these special diamonds in the last six months." 
 
 He said the huge cash injection from the diamond sale would allow the company to expand its operations in the area. 

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– One of the largest diamonds ever recorded has been pulled from the ground in Angola. Australia's Lucapa Diamond Company announced Monday that a 404.2-carat white diamond, about the length of a credit card, had been discovered. The find came at a 1,148 square-mile site that has since 2015 given up more than five dozen "large special diamonds," reports CNNMoney. It's the largest to come out of Angola by far, besting the stats of a 217.4-carat diamond found in 2007, per a release from the company. And size isn't the diamond's only impressive attribute: It's also colorless—D-colored being the rarest and probably most valuable grade, per CNNMoney—and, as a Type IIa gem, is nearly flawless. "When we first looked at the property ... untouched ground, [435 miles] inland from the coast, you are talking about a very, very remote area," Lucapa's chairman tells Australia's ABC News. "The results today are a wonderful vindication of eight years of pretty hard work." He adds the "spectacular" rock—believed to be the 27th largest diamond ever recorded and the largest ever recovered by an Australian diamond miner—is likely worth more than $20 million. (Miners recently found the second-largest diamond ever.)