An exquisite gentleman's sapphire ring. Photo Bonhams.

The raised cushion-shaped sapphire, weighing 20.53 carats, ring size 10. Estimate HK$ 2 million - 3 million (€190,000 - 280,000)

Accompanied by a SSEF report stating that the natural sapphire has no indications of heat treatment and originates from Ceylon (Sri Lanka). Report number 66366, dated 10 January 2013.

Accompanied by a Gubelin report stating that the natural sapphire has no indications of heat treatment and originates from Ceylon (Sri Lanka). Report number 13010099, dated 16 January 2013. Also accompanied by an appendix from Gubelin stating that unheated sapphire of this size are scarce.

Accompanied by a GRS report stating that the natural sapphire is of "cornflower blue" colour, has no indication of thermal treatment and originates from Ceylon (Sri Lanka). Report number GRS2013-023266, dated 19 February 2013.

Bonhams. FINE JEWELLERY & JADEITE. Hong Kong, Admiralty, 21 May 2014 - www.bonhams.com