Williamson Pink Star: All about the rare pink diamond that sold for nearly $50 million

A rare 'fancy vivid' pink diamond was sold for $49.9 million in Hong Kong on Friday, setting a world record for the highest price per carat for a diamond sold at auction.

The pink diamond 'Williamson Pink Star' weighs 11.15-carat and was auctioned by Sotheby’s Hong Kong., AP reported. Though originally estimated at $21 million, it was sold for $392 million Hong Kong dollars ($49.9 million.

The Williamson Pink Star is the second-largest pink diamond to appear at auction.


Pink diamonds are among the rarest and most valuable of the coloured diamonds. The source of their pink color is debated, and one of the widely accepted theories is that the pink is caused when the diamond faces shear pressure during its formation.

"The presence of nitrogen creates yellow diamonds, and boron forms blue diamonds. Curiously, there are no trace elements found in pink diamonds. Instead, the cause of the pink hue is thought to be caused by a distortion in the diamond’s crystal lattice, created by intense heat and great pressure after the stone’s formation," Sotheby's says.

Colour, and not just size, is considered while determining the value of a pink diamond. Larger a pink diamond, and better its color, the more valuable it will be. The Gemological Institute of America grades pink diamonds based on their colour as: Faint, Very Light, Light, Fancy Light, Fancy, Fancy Intense, Fancy Vivid.

The Williamson Pink Star draws its name from two legendary pink diamonds. The first is the 23.60-carat Williamson diamond which was presented to the late Queen Elizabeth II as a wedding gift in 1947. The second is the 59.60-carat Pink Star diamond that sold for a record $71.2 million at auction in 2017.

Pink diamonds were first discovered in the Kollur mines in India during the early 17th century, and has since been mined in mined in Australia. Brazil, South Africa, Tanzania, Canada etc.