The highlight of Sotheby’s Australia auction, a 0.82-carat oval-cut fancy purplish red-color diamond from the Argyle Mine failed to sell at the auction. It’s expected sale price was set between $0.76 million -$1.1 million, but its biding price opened at $480,000 and closed $490,000, reports say. %% The diamond is of SI1 clarity and set between a pair of brilliant, round-cut, fancy blue diamonds mounted in platinum. It was the first red diamond and the first stone from the Argyle Mine to be auctioned in Australia, reports add. %% The Sotheby’s Australia auction offered 250 lots in sale, with antique and contemporary jewellery, reports add.