A magnificent diamond single-stone ring, circa 1940. Estimate: £150,000 - 200,000. photo courtesy Bonhams A magnificent late art deco diamond ring is the highlight of the Bonhams Fine Jewellery sale which will take place in New Bond Street on September...

A Belle Epoque emerald and diamond ring, by Cartier The square-cut emerald within an old-cut diamond surround to the calibré-cut emerald frame, diamond border and two-stone corners, circa 1915, in Cartier red leather case. Signed Cartier, No. Pt 97091....