$30m High Estimate for Bunny Mellon's Blue Diamond

(IDEX Online) - A 9.51-carat fancy vivid blue diamond that set a world record when it was sold in 2014 is to be auctioned by Christie's Geneva in November.

The Mellon Blue, which belonged to the late horticulturalist and philanthropist Rachel Lambert (Bunny) Mellon - known as the American Garden Queen - carries a $20m to $30m estimate.

The stone has since been re-cut for greater clarity (increased from VVS1 to IF, and down in weight from 9.75 carats to 9.51 carats) and re-set as a ring.

"This stunning fancy vivid blue diamond, once belonging to America's Garden Queen, and is among the finest coloured diamonds to appear for sale at auction," said Rahul Kadakia, Christie's international head of jewelry.

It was originally set as a pendant when it sold at Sotheby's New York for sold for $32.6m in November 2014, shortly after Mellon's death, aged 104.

The Mellon Blue set an auction record at the time for a blue diamond. It was bought by a private Hong Kong collector, who paid more than twice the pre-sale high estimate of $15m and renamed the stone Zoe Blue.

That record was broken in April 2022 by the De Beers Blue, a 15.10-carat fancy vivid blue diamond that sold for $57.5m at Sotheby's Hong Kong.

The stone will be previewed in Hong Kong ahead of the 11 November Magnificent Jewels auction in Geneva.

Pic of Mellon Blue courtesy Christie's.