Black jadeite, jadeite and gem-set ring, by Alessio Boschi. Photo courtesy Tiancheng International Auctioneer Limited

Set with a pear-shaped black jadeite cabochon, highlighted by green jadeite cabochons, decorated by multi-coloured gems extending to the bifurcated shank, the gallery embellished with yellow gold palmette-shaped openwork. Jadeite measuring approximately 25.09 x 14.80 x 7.92mm. Mounted in 18 karat white gold. Signed Alessio Boschi. Ring size: 7 1/2. Estimate US$13,000 - 20,000

Accompanied by Hong Kong Gems Laboratory report numbered GL77848 dated 27 March 2013, stating that the black jadeite is natural, known in the trade as "A jade".

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/