HONG KONG, March 29 -- A 59.60-carat oval pink diamond will be auctioned at Sotheby's Hong Kong jewels and jadeite spring sale on April 4.

It is the largest internally flawless fancy vivid pink diamond that the Gemological Institute of America (GIA) has ever graded.

Estimated at over 60 million U.S. dollars, the Pink Star will lead the spring auction in Hong Kong.

Mined by De Beers in Africa in 1999, the 132.5-carat rough diamond was meticulously cut and polished for over two years and transformed into a 59.60-carat stunning gemstone.

The Pink Star has received the highest color and clarity grades from GIA for pink diamonds and has been found to be part of the rare subgroup comprising less than 2 percent of all gem diamonds.