On October 19th, Sotheby's will auction off a dazzling array of jewels, from a 29.53 carat flawless pear-shaped diamond ring to exquisite pieces designed by Van Cleef & Arpels, Bulgari, David Webb and Tiffany & Co. The sale, which will take place at Sotheby's New York headquarters, will feature jewels from private American collections, as well as a selection of high quality white diamonds and…