Sapphire and diamond ring, Boucheron. Photo courtesy Sotheby's

Centring on cabochon sapphire weighing 12.21 carats, within a double frame of brilliant-cut diamonds, size 51, signed Boucheron, numbered, French assay mark. Estimate 38,000 — 52,000 CHF

Accompanied by a duplicate of Gübelin report no. 0607159, stating that the sapphire is of Burmese origin, with no indications of heating.