Pink diamond worth millions shown ahead of auction

London - Sotheby's is displaying the startling "pink star" diamond in London before it will be auctioned in Hong Kong next month.

The company says the gem should fetch more than $60m when put on the block on April 4, which would represent a record for a pink diamond sold at auction.

It said on Monday that the 59.60-carat gem is the largest flawless fancy pink diamond ever graded by the Gemological Institute of America.

Sotheby's jewellery division chief David Bennett said the gem's size and colour "surpassed any known pink diamond recorded in history." It was mined in Africa in 1999.

The company sold the "Blue Moon of Josephine" diamond for $48.5m in Geneva in 2015.