Miners in north-east Angola have discovered a rare, pure pink diamond they believe to be the largest rough diamond of its kind to be unearthed in 300 years.

The Australian site operator named the 170-carat stone The Lulo Rose.

It said the diamond will be sold at international tender by the Angolan state diamond marketing company.

The find in the Lulo alluvial mine was welcomed by the Angolan government.

“This record and spectacular pink diamond recovered from Lulo continues to showcase Angola as an important player on the world stage for diamond mining,” Minerals Resources Minister Diamantino Azevedo is quoted as saying in a statement.

Similar stones, once cut and polished, have sold for record-breaking prices.

The Pink Star, a 59-carat pink diamond, sold for $71.2m in 2017 – the most expensive ever.