Diamonds of D colour grade and other fancy coloured diamonds will highlight Bonhams Fine Jewellery sale slated at New Bond Street on 30th April. The highlight of the sale is a white diamond ring by Piaget. The ring bears a marquise-cut diamond, weighing 8.97 carats and graded D-colour - the top colour grade for white diamonds. This VVS2 diamond is classified by GIA as Type IIa and the lot carries a sale estimate of US$ 410,000 - 580,000.

The sale will also offer a round brilliant-cut weighing 5.00 carats graded by the GIA as D colour, VVS2 clarity, Type IIa. It carries an estimate of US$ 200,000-$300,000. A Fancy Yellow diamond of 24.59 carats is a step-cut diamond ring being offered with an estimate of US$ 250,000-$410,000.

Amongst the fine quality coloured gems is a Colombian emerald ring of exceptional colour and of 10.49 carats and a ring set with a cushion-shaped Burmese sapphire weighing 22.18 carats, mounted between two demi-lune-shaped diamonds. The sale is also offering period jewellery including a rare “Orange Tree” brooch made by Cartier Paris in 1914 and exemplifying the early 20th century quality and innovation.