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

Set with a cushion-cut diamond, weighing approximately 27.03 carats, mounted in platinum - Estimate $2,500,000 - $3,000,000

With report 5121072749 dated 3 May 2010 from the Gemological Institute of America stating that the diamond is D color, VVS1 clarity, with excellent polish and excellent symmetry

Accompanied by a supplemental letter stating that the diamond has been determined to be a Type IIa diamond. Type IIa diamonds are the most chemically pure type of diamond and often have exceptional optical transparency. Type IIa diamonds were first identified as originating from India (particularly from the Golconda region) but have since been recovered in all major diamond-producing regions of the world. Among famous gem diamonds, the 530.20 carat Cullinan and the 105.60 carat Koh-i-noor, are examples of Type IIa

A pair of diamond ear studs. Photo: Christie's Images Ltd 2010

Each set with a circular-cut diamond, weighing approximately 7.85 and 7.67 carats, mounted in platinum - Estimate $1,800,000 - $2,500,000

With report 5111272178 dated 2 March 2010 from the Gemological Institute of America stating that the diamond, weighing approximately 7.85 carats, is D color, flawless clarity, with excellent polish and excellent symmetry

With report 2125160268 dated 19 May 2010 from the Gemological Institute of America stating that the diamond, weighing approximately 7.67 carats, is D color, VVS1 clarity, with excellent cut and excellent symmetry

A magnificent diamond ring. Photo: Christie's Images Ltd 2010

Set with a circular-cut diamond, weighing approximately 37.08 carats, to the pavé-set diamond hoop, mounted in platinum - Estimate $1,300,000 - $1,500,000

With report 15834096 dated 3 May 2007 from the Gemological Institute of America stating that the circular-cut diamond, weighing approximately 37.08 carats, F color, SI1 clarity, with excellent cut, excellent polish and excellent symmetry

Notes: The circular-cut diamond of 37.08 carats being offered in this sale is a truly exceptional gemstone. It is the largest circular-cut F color diamond to have appeared at auction and is graded by the Gemological Institute of America as having the rare combination, in such large diamonds, of excellent polish, excellent symmetry and excellent cut - a grade only warranted for circular-cut diamonds of superior status.

In order to cut a round diamond there will always be a far greater weight loss from the original crystal than there would be with any other shape, like a pear, heart, marquise or rectangle in order to best fit the irregular shape of the fractured crystals that are predominant. Also, when the color of the diamond crystal is extremely high, as is the case here, there is even less incentive to cut a round stone and lose 50-60 percent of the weight of the original crystal. At 37.08 carats, F color, this is a truly sensational diamond to be offered for sale at auction.

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

Each suspending a cushion-cut diamond, weighing approximately 12.02 and 11.60 carats, within a single-cut diamond surround, from a single-cut diamond link, to the diamond-set hoop, mounted in platinum - Estimate $550,000 - $650,000

A diamond ring. Photo: Christie's Images Ltd 2010

Set with a square-cut diamond, weighing approximately 6.54 carats, flanked on either side by a tapered baguette-cut diamond, mounted in platinum - Estimate $180,000 - $220,000

With report 17159651 dated 26 June 2008 from the Gemological Institute of America stating that the diamond is G color, VS1 clarity

A diamond line bracelet. Photo: Christie's Images Ltd 2010

Designed as an alternating series of graduated oval, circular and rectangular-cut diamonds, joined by a marquise-cut diamond clasp, mounted in platinum, 7 ins. - Estimate $170,000 - $200,000

With sixteen reports dated from 20 September 1994 to 16 October 2008 from the Gemological Institute of America stating that sixteen of the diamonds, weighing from approximately 1.02 to 3.18 carats, range from H to K, faint brown color and from internally flawless to I1 clarity

A diamond riviere necklace. Photo: Christie's Images Ltd 2010

Composed of sixty-five graduated old mine and old European-cut diamonds, mounted in platinum-topped 18k gold, 16½ ins. - Estimate $160,000 - $200,000

A diamond "legacy" ring, by Tiffany & Co. Photo: Christie's Images Ltd 2010

Set with a modified cushion-cut diamond, weighing approximately 5.56 carats, within a circular-cut diamond surround, gallery and graduated circular-cut diamond shoulders, with collet-set diamond accents, mounted in platinum, in a Tiffany & Co. black suede box. Signed Tiffany & Co., no. 19104257 - Estimate $150,000 - $250,000

A diamond ring. Photo: Christie's Images Ltd 2010

Set with a rectangular-cut diamond, weighing approximately 5.49 carats, to the graduated baguette-cut diamond shoulders, mounted in platinum - Estimate $150,000 - $200,000

With report 2111325228 dated 4 November 2009 from the Gemological Institute of America stating that the diamond is F color, VVS2 clarity

A diamond ring. Photo: Christie's Images Ltd 2010

Set with a cut-cornered rectangular-cut diamond, weighing approximately 5.77 carats, flanked on either side by a trillion-cut diamond, mounted in platinum - Estimate $85,000 - $100,000

With report 2101355441 dated 22 October 2008 from the Gemological Institute of America stating that the diamond is G color, SI1 clarity

A diamond ring, by Tiffany & Co. Photo: Christie's Images Ltd 2010

Set with a cushion-cut diamond, weighing approximately 3.03 carats, within a circular-cut diamond surround, to the circular-cut diamond shoulders, mounted in platinum. Signed Tiffany & Co. Estimate $80,000 - $120,000

With report 2105466637 dated 16 December 2008 from the Gemological Institute of America stating that the diamond is D color, internally flawless clarity

A diamond necklace. Photo: Christie's Images Ltd 2010

Suspending a pear-shaped diamond, weighing approximately 4.20 carats, from a graduated series of pear-shaped diamonds, mounted in platinum, 15¼ ins. Numbered 929 - Estimate $80,000 - $120,000

With report 2115128803 dated 15 September 2009 from the Gemological Institute of America stating that the diamond is F color, SI1 clarity

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