Updated 6:54pm 29 May 2012

Flawless show

ONE of the rarest precious stones in the world is being put on show to the public.

The fancy vivid blue diamond is expected to fetch between £4m and £6m at Sotheby’s Magnificent Jewels sale in Geneva, on May 12.

The gem, described as cushion-shaped and flawless, owes its distinctive colour to the presence of the chemi-cal element boron during the stone’s formation.

It was discovered last year in South Africa.

Share