Lot 279. Important 45.74 carats 'royal blue' Burmese sapphire and diamond ring, Van Cleef & Arpels. Estimate 685,000 — 885,000 CHF. Lot sold 1,455,000 CHF. Photo: Sotheby's.

Set with a step-cut sapphire weighing 45.74 carats, between tapered baguette diamond shoulders, size 49, sizing band, signed Van Cleef & Arpels, numbered, assay mark. 

Accompanied by SSEF report no. 90968 and Gübelin report no. 17080185, both stating that the sapphire is of Burmese origin, with no indications of heating, 'royal blue' colour, the SSEF report together with an appendix letter.

Note: "The described sapphire exhibits an impressive size and weight of 45.740 ct, combined with an exceptional purity and attractive well saturated blue colour. 

The few inclusions found by microscopic examination are consistent with those found in sapphires from the classic mines along the Mogok Gemstone Tract in Burma (Myanmar). Its attractive and saturated blue colour, poetically also referred to as 'royal blue', is due to a combination of well-balanced trace elements in the gemstone, which are typical and characteristic for fine sapphires from Mogok, Burma".

Excerpt from the SSEF appendix letter

Sotheby's. Magnificent Jewels and Noble Jewels, Geneva, 15 Nov 2017, 10:30 AM