Lot 310. Attractive 16.34 carats Kashmir cushion-shaped sapphire and diamond ring. Estimate 690,000 — 985,000 CHF. Photo Sotheby's

Set with a cushion-shaped sapphire weighing 16.34 carats, within a frame of brilliant-cut diamonds, size 52, sizing band.  

Accompanied by SSEF report no. 71490, dated 30 October 2013, and Gübelin report no.16090077, dated 19 September 2016, each stating that the sapphire is of Kashmir origin, with no indications of heating; together with appendix letters.   

Note: "The described gemstone exhibits an impressive size and weight of 16.341 ct combined with an attractive saturated blue colour and an excellent purity".

Excerpt from the SSEF appendix letter

Sotheby's. Magnificent Jewels and Noble Jewels, Genève, 16 nov. 2016, 10:30 AM