Sapphire and diamond ring. Photo courtesy Tiancheng International Auctioneer Limited

Centring on a step-cut sapphire weighing 12.04 carats, flanked by two trillion-cut diamonds. Mounted in 18 karat blackened gold. Ring size: 5 1/2. Estimate US$110,000 - 160,000

Accompanied by GRS report numbered GRS2012-021443 dated 22 March 2012, stating that the 12.04 carat sapphire is natural, of Sri Lankan origin, Vivid Blue (GRS type "Royal Blue") colour, with no indication of thermal treatment.

Tiancheng International Auctioneer Limited. SPRING AUCTION 2013 JEWELLERY AND JADEITE. 15 Jun · 3 pm. Hong Kong Headquarters 30/F Bank of China Tower 1 Garden Road, Central Hong Kong http://www.tianchengauction.com/