HONG KONG: A 10.10 carat vivid blue diamond is expected to set the record for the most expensive piece of jewellery sold at auction in Asia despite an ongoing growth slowdown in China’s economy, Sotheby’s said on Friday. The “De Beers Millennium Jewel 4” is expected to fetch between $30 million and $35 million at the April 5 sale in Hong Kong, and is described by the auction house as the largest oval blue diamond ever to appear at auction and “internally flawless”. The diamond is slightly larger than an almond in size.