A pair of early 20th century pearl and diamond pendent earrings. photo courtesy Bonhams

Each drop-shaped pearl of light grey or white tint, measuring 9.9-10.0mm., surmounted by a cap of chevron design set with rows of single and rose-cut diamonds, suspended from an articulated line of single and old brilliant-cut diamonds, length 6.2cm. Estimate: £10,000 - 12,000

Accompanied by a certificate from The Gem and Pearl Laboratory stating that the pearls were found to be natural and of saltwater origin. Certificate number 03089, dated 26th July 2010.

An early 20th century cultured pearl and diamond bow brooch. photo courtesy Bonhams

The early 20th century double bow millegrain-set throughout with old brilliant and single-cut diamonds, suspending a highly articulated tassel of similarly cut diamonds, the whole with later cultured pearl and brilliant-cut diamond highlights, composite, diamonds approximately 5.00 carats total, length at longest point 7.8cm. approximately. Estimate: £3,000 - 4,000

According to the vendor, the alterations to this brooch were undertaken by David Webb.

Bonhams. Fine Jewellery, 22 Sep 2010 New Bond Street www.bonhams.com