An unmounted fancy-coloured diamond. Photo: Bonhams.

The cushion-shaped fancy brownish yellow diamond weighing 2.00 carats. Estimate £6,000 - 8,000 (€7,200 - 9,600)

Accompanied by a report from GIA stating that the 2.00 carat diamond is Fancy Brownish Yellow, natural colour, VS2 clarity. Report number 2121391364, dated 29 July 2010.

A pair of unmounted fancy-coloured diamonds. Photo: Bonhams.

Comprising a cushion-shaped fancy pink diamond weighing 0.52 carat and a cushion-shaped fancy intense pink diamond weighing 0.41 carat (2). Estimate £15,000 - 20,000 (€18,000 - 24,000)

Accompanied by a report from GIA stating that the 0.52 carat diamond is Fancy Pink, natural colour, VS2 clarity. Report number 2136197356, dated 19 April 2012.

Accompanied by a report from GIA stating that the 0.41 carat diamond is Fancy Intense Pink, natural colour, SI1 clarity. Report number 1128622706, dated 21 October 2011.

Bonhams. FINE JEWELLERY, 30 Apr 2014, London, New Bond Street - www.bonhams.com