A fancy purplish red Argyle diamond ring, estimated at up to US$919,000 is the highlight of Sotheby's Australia first stand alone jewelry auction, which will consists of more than 250 lots of antique and contemporary jewelry.

This is the first red diamond to ever be offered for public auction in Australia and it is accompanied by a letter from Argyle Diamonds attesting to the rarity of the diamond. Despite the notable discovery of the Argyle pink diamond deposits in Western Australia in 1987, less than a handful of red diamonds have been discovered.

The oval diamond of fancy purplish red color weighing 0.82 carat is claw set between a pair of fancy blue diamonds in a round brilliant cut diamond surround, mounted in platinum. Diamond connoisseurs have long considered red diamonds to be among the most precious and rarest of all diamonds. While the cause of these diamonds color is not yet thoroughly understood, it is generally accepted that the red color results from structural features in the diamond's crystal lattice.

Following on from the exhaustion of the fabled Indian diamond mines in the 1700s, recent discoveries of small diamonds in the purplish red hues have been reported from Brazil, Borneo, India, South Africa and Venezuela.

The sale also contains jewels by the distinguished houses of Cartier, Bvlgari and Tiffany & Co, Paspaley South Sea pearls, GIA certified white, yellow and pink solitaire diamonds, and prestigious watches by Rolex and Cartier.