18 karat white gold, pink star sapphire and diamond ring, Sifen Chang. Photo: Sotheby's.

The oval cabochon pink star sapphire weighing 37.02 carats, framed and accented by round diamonds weighing 1.82 carats, size 5¾, with Chinese characters for Sifen Chang. Estimation 20,000 — 30,000 USD 

Accompanied by Gübelin report no. 12011017 stating that the sapphire is natural, with no indications of heating.

Sotheby's. Important Jewels. New York | 24 sept. 2013 - http://www.sothebys.com