19.88 kt natural Burma untreated Red Spinel and Diamond ring. Estimate HK$180,000 - 280,000 (US$23,000 - 36,000). Photo Tiancheng International

Centring on a cushion-shaped red spinel weighing 19.88 carats, within a surround decorated with oval, baguette and brilliant-cut diamonds extending to the shoulders, mounted in 18 karat white gold. Ring size: 6½

Accompanied by LOTUS report numbered 7040-6714, dated 30 June 2015, stating that the 19.88 carat spinel is natural, Red colour, of intense saturation and deep tone, of Burmese origin, with no indications of heating or treatment.

Tiancheng International. HONG KONG AUTUMN AUCTION, Jewellery and Jadeite