RAPAPORT... A Cartier twin sapphire and diamond ring fetched more than double its low estimate at Skinner Auctioneers. The piece, which was created in the 1950s, features twoKashmir sapphires weighing 5.34 and 4.91 carats, and tapered, baguette-cutdiamonds. It sold for $873,000 at the September 17 Important Jewelry sale inBoston against a presale estimate of $300,000 to $500,000. Skinner also sold an antique ring set with a pear-shapedcabochon Burmese ruby surrounded by old mine-cut diamonds for $171,000. Thefinal price was more than 20 times its estimate of $5,000 to $7,000. In total, the auction garnered $2.5 million. Image: The Cartier twin-stone sapphire ring. (Skinner Auctions)