A purple sapphire and diamond ring. Photo Christie's Image Ltd 2014

Of bombé design, set with an oval-cut purple sapphire, weighing approximately 7.29 carats, trimmed by circular-cut diamonds, to the rose-cut pink and purple sapphire surround, mounted in 18k white gold, with French assay mark and maker's mark. Estimate $20,000 – $25,000

With report CS 60618 dated 21 April 2014 from the American Gemological Laboratories stating that it is the opinion of the Laboratory that the origin of this purple sapphire would be classified as Madagascar. No gemological evidence of heat

Christie's. IMPORTANT JEWELS,10 June 2014, New York, Rockefeller Plaza- http://www.christies.com/