Rare jewellery being auctioned - 06/05/2010

Sotheby's is hosting the Magnificent Jewels and Noble Jewels sale at the Beau-Rivage hotel in Geneva on May 11th but the items up for grabs are being displayed from May 8th.

A highlight of the sale is a group of white and coloured diamonds, including a pear-shape blue diamond weighing 5.02 carats and an emerald-cut white diamond that weighs 52.82 carats. Both are set as separate rings.

The Gemological Institute Of America has given the rare white diamond a first class rating because of its flawless clarity. The highest bidder will be allowed to name the stone which is estimated to fetch around $7 million (£4.7 million).

French jeweller Alexandre Reza designed the ring with the blue stone which is mounted alongside a white diamond of the same shape. It is expected to sell for between $4 million (£2.7 million) and $7 million (£4.7 million).

A spokesperson for Sotheby's said: "We present a stunning selection of outstanding diamonds and coloured stones, glamorous signed pieces by the most prestigious houses and important jewels with noble provenance."

Another highlight of the auction is a diamond necklace by Chiappe, weighing more than 160 carats. It once belonged to an Italian noble family and is likely to sell for between $1.4 million (£927,000) and $2.1 million (£1.39 million).