RAPAPORT... The Williamson Pink Star diamond has become the second-most valuable jewel ever sold at auction, following a 'bidding frenzy' at Sotheby's Hong Kong.After a 20-minute battle, which included 50 bids, the cushion-cut, 11.15-carat, fancy-vivid pink, internally flawless diamond ring sold for $57.7 million, nearly three times its $21 million high estimate, Sotheby's said following the one-off sale on October 7. The piece, which was purchased by an American collector, is only surpassed by the CTF Pink Star, an oval mixed-cut, 59.60-carat, fancy-vivid-pink, internally flawless diamond which Chow Tai Fook bought at Sotheby's Hong Kong for $71.2 million in 2017. The Williamson Pink Star set a record per-carat price for any diamond or gemstone sold at auction, Sotheby's noted. The diamond achieved $5.2 million per carat, beating out the previous record of $4 million per carat set by the 12.03-carat, internally flawless Blue Moon of Josephine sold at Sotheby's Geneva in 2015."This result was truly remarkable," said Jonathan Abram, brand director for Hong Kong-based jewelry and gemstone dealer Ronald Abram. "No one was expecting the world record to be broken...but at auction you don't have limitations on what you can get for a stone. You simply need two or more bidders with spending power and appetite. Sotheby's should be happy with their results, especially in today's market, with fewer mainland Chinese buyers who are vital to the high jewelry market."Switzerland-based manufacturer Diacore cut the Williamson Pink Star from a 32.32-carat rough it purchased from Petra Diamonds for $13.8 million in 2021. The miner recovered the stone from its Williamson mine in Tanzania."What an honor to have had the opportunity to handle a diamond of such breathtaking beauty," said Wenhao Yu, chairman of jewelry and watches at Sotheby's Asia. "History was made in Hong Kong [at the auction]. Ultimately, what we have witnessed in the room reflects the appetite for rare and impeccable gemstones amongst global collectors."In addition to the stand-alone auction, Sotheby's also held its regular Magnificent Jewels auction in Hong Kong. In total, that sale garnered HKD 294.7 million ($37.5 million), with a jadeite and diamond pendant necklace taking the top spot, fetching HKD 33 million ($4.2 million). A jadeite bead, diamond and ruby necklace brought in HKD 28.4 million ($3.6 million) and an unmounted, round brilliant-cut, 22.88-carat, D-flawless diamond went for HKD 17.1 million ($2.2 million), both just missing their low estimates. Image: The Williamson Pink Star diamond. (Sotheby's)