RAPAPORT... Sotheby's will auction two flawless white diamonds weighingover 50 carats each, estimated at a combined price of more than $15 million. The first is a round brilliant-cut, 51.71-carat stone,estimated at $8.2 million to $9.5 million, while the second is an oval-shaped, 50.39-caratdiamond, with an estimated price of $7.3 million to $8 million. Both stones areD color, flawless, type IIa and the largest of their shape to be sold atauction. The stones will be previewed in London on April 6, and go onsale at Sotheby's Magnificent Jewels and Noble Jewels auction in Geneva on May15. Sotheby's also said it had sold a 102.34-carat white diamond-the only known round brilliant, flawless diamond over 100 carats -in a private sale. While the company did not reveal who bought it and for howmuch, it said the purchase price far exceeded any price per carat paid for acolorless diamond at auction. The current record for a white diamond is$260,252 per carat, it noted. "Having witnessed the enormous effect of the 102.34-caratstone on those who saw it, we are now thrilled to bring to...market two moretruly exceptional stones, both of which are among the largest, highest-qualitywhite diamonds ever to come to auction," said David Bennett, worldwide chairmanof Sotheby's international jewelry division. "Diamonds like these have alwayscaptivated collectors and connoisseurs alike, and continue to do so today."