Lot 459. Very fine 40.13 carats Mogok Burmese 'Royal Blue' sapphire and diamond ring. Estimate 780,000 — 1,360,000 CHF. Lot sold 3,190,000 CHF. Photo Sotheby's

Set with a cushion-shaped sapphire weighing 40.13 carats, within a surround of marquise-shaped diamonds,size 48. 

Accompanied by SSEF report no. 82356 and Gübelin report no. 9810043, dated 14 October 1998, each stating that the sapphire is of Burmese origin, with no indications of heating, 'royal blue' colour; together with an appendix letter expressing the quality and the rarity of the stone, and a Gübelin report. 

Note: "The described gemstone exhibits an important size and weight of 40.13 ct, combined with an attractive and saturated colour and a very fine purity. Its colour is further pronounced by its well-proportioned cutting style, resulting in vivid blue hues due to multiple internal reflections... Its attractive blue colour - poetically also referred to as 'royal blue' - is due to a combination of well-balanced trace elements in the gemstone, typical and characteristics for the finest sapphires of Mogok, Burma". Excerpt from the SSEF appendix letter.

Sotheby's. Magnificent Jewels and Noble Jewels, Genève, 11 nov. 2015, 10:00 AM