Aust miner finds 172 carat diamond

Australian miner Lucapa has found a large, nearly pure diamond at its main operation in Angola, the fifth weighing more than 100 carats it has found this year.

Australian miner Lucapa Diamond Company has unearthed a large almost pure diamond at its main Angolan mine.

The 172.67 carat diamond weighs about 35 grams and Lucapa says it is a Type IIa D-colour stone, meaning it's almost entirely devoid of impurities and colourless.

Chief executive Steve Wetherall said the "exceptional" stone was recovered from alluvial operations at Lulo, about 630km east of the Angolan capital Luanda.

"Is is the fifth over 100 carat diamond recovered from the mining operations so far in 2016 and the sixth in total," he said in a statement on Monday.