Lot 172. A fine 20.38 carats oval-cut Burma 'Royal Blue' sapphire and diamong ring, by Harry Winston. Estimate CHF300,000 – CHF500,000 ($438,690 - $645,132). Photo Christie's Image Ltd 2016.

Set with an oval-cut sapphire, weighing approximately 20.38 carats, and circular-cut diamond twin surround cluster, between pear-shaped diamond shoulders, ring size 5 ½, mounted in platinum and gold, in blue leather Harry Winston case. Unsigned

Accompanied by report no. 16010179 dated 5 February 2016 from the Gübelin GemLab stating that the origin of the sapphire is Burma (Myanmar), with no indications of heating, and an Information Sheet on 'Unheated sapphires',and that the colour may also be called 'Royal Blue'.

Further accompanied by copy of an invoice dated 23 November 1990 from Harry Winston.

Christie's. GENEVA MAGNIFICENT JEWELS, 18 May 2016, Geneva