Coloured diamonds have been making the headlines at all the major auction houses this year, and there are no signs of interest waning among buyers this autumn. Among the top lots at Bonhams' Fine Jewellery Sale in London on 18 September is a ring set with a fancy intense blue diamond weighing 1.02ct - a stunning and rare stone that is sure to attract plenty of interest (estimate £160,000-£190,000).

The highlights of Bonhams' autumn sale are a good indication of the trends that have emerged this year in antique jewellery. Natural pearls have been achieving record high prices at auction so all eyes wil be on Lot 135, a pair of art deco natural pearl and diamond pendant earrings circa 1925. Framed within the geometric design - so indicative of the deco era - are two beautiful teardrop-shaped natural pearls that are sure to appeal to collectors.

More natural pearls are included in the sale - a simple string with a very storied history (Lot 18). The single row of pearls is said to have belonged to Oliver Cromwell's daughter Frances (1638-1720), who was captured wearing the necklace in a painting by John Michael Wright, which is on display at the Glasgow Museums Collection. Passed down through direct descendents of the Cromwell family for generations, this is a rare opportunity to own jewels of historic importance at a surprisingly reasonable price if they sell for their estimate of £6,000-£8,000.

The art deco era has been particularly embraced by the auction world this year. Lot 125, a rare art deco shoulder brooch signed Cartier, circa 1922, is a classic piece of deco design, with a tassel of seed pearls swinging from a cascade of onyx hoops, connected by diamond buckles. With its clear Oriental influences, a look closely associated with Cartier at the time, this 'brooch poignée' - drawer handle brooch - is estimated to achieve £25,000-£35,000.