RAPAPORT... A number of diamond pieces scored big at the most recent Christie's jewelry sale, outshining their presale estimates and driving an auction total of $2.8 million.The top seller was a ring featuring an old-cut, 25.14-carat diamond, which fetched $424,538 - more than double its $164,092 upper estimate, Christie's said last week.A pair of old-cut diamond earrings from 1960 also performed well at the sale, called Jewels & Watches Online: La Dolce Vita, which ran from March 1 to 10. The set, which contains two diamonds weighing 12.22 and 12.11 carats, brought in $339,630, more than triple its high estimate. Meanwhile, a ring set with a circular-cut, 4.30-carat diamond shot ahead of its $28,078 high estimate to sell for $67,926, and a diamond and sapphire ring garnered $56,606, outstripping its upper price. In total, Christie's sold 93% of items on offer at the auction, it noted.Image: The 25.14-carat diamond ring. (Christie's)