Emerald jewelry @ Christie's, New York Jewels, 15 June 2010, New York

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

Designed as a graduated series of cushion-cut emeralds, each within a circular-cut diamond surround, spaced by collet-set diamonds, to the circular-cut diamond clasp, mounted in platinum, 17 ins. Estimate $180,000 - $250,000

An emerald and diamond ring, by Van Cleef & Arpels. Photo: Christie's Images Ltd 2010

Set with a cut-cornered rectangular-cut emerald, weighing approximately 6.83 carats, within a circular-cut diamond surround, to the circular-cut diamond shoulders and platinum hoop, mounted in gold and platinum. Signed Van Cleef & Arpels, N.Y., no. 43367 - Estimate $100,000 - $150,000

With report CS 40486 dated 15 April 2009 from the American Gemological Laboratories stating that based on available gemological information, it is the opinion of the Laboratory that the origin of this emerald would be classified as Colombia. Enhancement: None

A sapphire, emerald and gold necklace, by Louis Comfort Tiffany, Tiffany & Co. Photo: Christie's Images Ltd 2010

The openwork plaque centering upon a circular-cut violet sapphire, surrounded by a cushion-cut sapphire and five cushion-cut emeralds, trimmed by smaller circular and hexagonal-cut sapphires and emeralds, to the three-row neckchain, comprising one strand of gold oblong spirals and scrolls between two strands of gold beads, the clasp set with a cushion-cut emerald, flanked by two circular-cut sapphires, mounted in gold, circa 1928, 15¼ ins. By Louis Comfort Tiffany, signed Tiffany & Co. Estimate $50,000 - $70,000

With a copy of a letter dated 18 September 1943 from Tiffany & Co. stating that the necklace was made under the personal supervision of Louis Comfort Tiffany

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

Set with a cushion-cut emerald, weighing approximately 7.68 carats, flanked on either side by a half moon diamond, mounted in platinum  Estimate $30,000 - $50,000

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

The front designed as a three swags of alternating marquise and circular-cut diamonds, each suspending a pear-shaped emerald, to the single-row marquise and circular-cut diamond backchain, mounted in 18k white gold, 16 ins. Estimate $25,000 - $35,000

A pair of art deco diamond, emerald, sapphire and pearl clips, by Oscar Heyman & Brothers. Photo: Christie's Images Ltd 2010

Comprising two old European and single-cut diamond clips, each of overlapping design, centering upon a vertical line of four pearls, trimmed with French-cut sapphires, bordered along the bottom by a line of emerald beads, spaced by seed pearls, mounted in platinum and white gold, circa 1930. Estimate $18,000 - $22,000

With maker's marks for Oscar Heyman & Brothers

Christie's, New York Jewels, 15 June 2010, New York, Rockefeller Plaza www.christies.com