An antique emerald and diamond bow brooch. Photo: Christie's Images Ltd 2010

The articulated ribbon bow mounted with graduated old-cut diamond collets alternated by square-shaped emeralds to the diamond line borders and three-stone centre, mounted in silver and gold, circa 1880, 12.0cm wide, in original purple velvet fitted case by Garrard & Co. Estimate £100,000 - £150,000 Price Realized £265,250

Notes: Cf. Diana Scarisbrick, Ancestral Jewels, Andre Deutsch, 1989, p.131

Large bow-knot or sévigneé brooches were popular from the second half of the seventeenth century onwards and were worn as bodice ornaments. By the 19th century these formal court jewels had largely been replaced by more naturalistic bows of smaller dimensions. The example offered here is of impressive proportions and is likely to have been made for ceremonial occasions when the Duchess was required to wear formal robes. It is a rare survival and is reminiscent of the equally large Newcastle Bow-Knot.

An emerald ring. Photo: Christie's Images Ltd 2010

Mounted with a hexagonal-shaped emerald to the geometric surround and hoop, 1940s. Estimate £45,000 - £55,000 Price Realized £103,250

Accompanied by report no. 0805142 dated 20 May 2008 from the Gübelin Gem Lab stating that the emerald weighing approximately 6.1 carats is of Colombian origin, with indications of minor clarity enhancement

A pair of emerald and ruby ear pendants, by Hemmerlé. Photo: Christie's Images Ltd 2010

Each composed of an emerald bead drop to the calibré-cut ruby-set cap suspended from a similarly-set surmount mounted with a pear-shaped cabochon ruby, 5.0cm long, with grey leather maker's pouch. Signed Hemmerle (2). Estimate £35,000 - £55,000 Price Realized £58,850

An emerald and diamond ring. Photo: Christie's Images Ltd 2010

The rectangular-shaped emerald weighing 3.47 carats to the shield-shaped diamond shoulders; Estimate £20,000 - £25,000 Price Realized £32,450

Accompanied by report no. 54903 dated 18 November 2009 from the SSEF Swiss Gemmological Institute stating that the emerald is of Colombian origin, with no indications of clarity enhancement

A pair of emerald and diamond ear pendants. Photo: Christie's Images Ltd 2010

Each composed of an emerald briolette drop with pavé-set diamond cap to the brilliant-cut diamond connection, suspended from a similarly-set diamond surmount mounted with a pear-shaped rose-cut diamond, 3.8cm long (2); Estimate £12,000 - £15,000 Price Realized £17,500

A rough emerald ring. Photo: Christie's Images Ltd 2010

The rough emerald weighing 94.98 carats to the four-claw mount and plain hoop; Estimate £500 - £700 Price Realized £8,125

An antique gold and emerald ring. Photo: Christie's Images Ltd 2010

Mounted with a rectangular-shaped cabochon emerald to the engraved shoulders and plain hoop, circa 1900; Estimate £6,000- £8,900 Price Realized £7,500

Christie's. Jewels - The London Sale, 1 December 2010, London, King Street www.christies.com