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The 404-carat diamond is reportedly the largest size ever found in Angola.

The chairman of Lacapa  Diamond, Miles Kennedy, while speaking to ABC news, said:

"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.

"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."

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Mr Kennedy had added that the "spectacular" white diamond, which is considered to be of excellent quality, could be valued at over $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."