A diamond-set brooch. Photo courtesy Bonhams.

The openwork navette-shaped plaque, set to the centre with a step-cut diamond, and throughout with graduated brilliant and baguette-cut diamonds, principal diamond approx. 1.05cts, remaining diamonds approx. 9.25cts total, length 4.8cm. Estimate £6,000 - 8,000 (€7,200 - 9,500)

Bonhams. JEWELLERY. London, Knightsbridge. 15 Jan 2014 - www.bonhams.com