Alexandrite and diamond ring. Photo courtesy Tiancheng International Auctioneer Limited

Centring on a cushion-shaped alexandrite weighing 2.91 carats, surrounded by marquise-shaped diamonds. Diamonds together weighing approximately 3.40 carats. Mounted in platinum. Ring size: 6. Estimate US$33,000 - 45,000

Accompanied by Gübelin report numbered 1010198 dated 03 November 2010, stating that the 2.91 carat alexandrite is natural, of Brazilian origin. 

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/