Lot 179. An important 17.97 carats Type IIa diamond solitaire ring. Estimate US$ 1,000,000 - 1,500,000 (€940,000 - 1,400,000). Photo: Bonhams.

An important diamond solitaire ring, weighing 17.97 carats, leads the Fine Jewellery auction at Bonhams on December 6 at 11am in New York. With a strong interest from collectors across the globe during its October sale, Bonhams yet again presents an excellent selection of diamond, noteworthy coloured gemstones and a plethora of signed jewellery, many from the Alhambra Collection by Van Cleef & Arpels.

This leading lot is a cut-cornered rectangular step-cut diamond, with tapered baguette-cut diamond shoulders mounted in platinum (estimate U.S. $1,000,000-1,500,000). This "ice" is accompanied by a Type IIa letter indicating a negligent amount of nitrogen in the diamond; and to the laymen, adding the rare quality of appearing liquid, purest water. Other historical stones that possess this limpid quality of exception transparency are: the Cullinan; the Koh-i-Noor and the Hope Diamond.

Lot 179. An important 17.97 carats Type IIa diamond solitaire ring. Estimate US$ 1,000,000 - 1,500,000 (€940,000 - 1,400,000). Photo: Bonhams.

centering a cut-cornered rectangular step-cut diamond, weighing 17.97 carats, with tapered baguette-cut diamond shoulders; mounted in platinum; size 6 3/4

Accompanied by GIA report # 6173989040, dated October 27, 2016, stating the diamond as: D color, VS1 clarity, Type IIa. 

Type IIa diamonds make up less than 2% of all natural diamonds and are almost pure carbon. They are so exceptional because they contain very little nitrogen, or none at all, which means that light can easily pass through the diamond and bounce back to the beholder's eye, producing a stunning, colourless appearance. Many of the most famous diamonds throughout history have been Type IIa: the world's largest cut diamond - the Cullinan, the Koh-i-Noor & the Hope Diamond are, but a few, examples.

A diamond and ruby necklace designed as an articulated, marquise, baguette and round brilliant-cut diamond ribbon (total diamond weight approximately 48 cts) is among the highlights of the sale. This piece simulates a scarf and is enhanced by fine unheated Burma rubies (estimate U.S. $100,000-150,000). Another fabulous diamond and unheated Burma ruby jewel is a bracelet by Tiffany & Co. with a total diamond weight of approximately 20.50 cts (estimate U.S. $50,000-70,000).

Lot 171. A diamond and Burmese ruby necklace. Estimate US$ 100,000 - 150,000 (€94,000 - 140,000). Photo: Bonhams.

designed as an articulated, marquise, baguette and round brilliant-cut diamond ribbon, enhanced by oval and round mixed-cut rubies, estimated total diamond weight: 48.00 carats; mounted in platinum; length: 14 3/4in.

Accompanied by AGL report # CS 1078965, dated October 14, 2016, stating the rubies as: Burma (Myanmar) origin, no indications of heat or clarity enhancement.

Also on the block is a very rare Kashmir sapphire and diamond ring by Shreve & Co. circa 1900. This sapphire (weighing approximately 6.90cts) exudes a rich saturated blue, and is accompanied by a laboratory certificate denoting "Classic" Kashmir (estimate U.S. $70,000-90,000).

Lot 178. A 6.90 carats Kashmir sapphire and diamond ring, Shreve & Co., circa 1900. Estimate US$ 70,000 - 90,000 (€66,000 - 85,000). Photo: Bonhams.

centering a cushion mixed-cut sapphire, weighing approximately 6.90 carats, within a raised gallery of old European-cut diamonds and scrolled metal work; signed; accompanied by a signed box; estimated total diamond weight: 1.00 carat; mounted in platinum and 18k gold; size 6 1/2

Accompanied by AGL report # CS 1078740, dated October 12, 2016, stating the sapphire as: Classic Kashmir origin, no indications of heat or clarity enhancement. 

Other highlights include:

Lot 174. An Art Deco Colombian emerald and diamond brooch, circa 1930. Estimate US$ 30,000 - 50,000 (€28,000 - 47,000). Photo: Bonhams.

of geometric triangular design, centering an epaulet step-cut emerald, weighing approximately 4.75 carats, enhanced by triangular, square, rectangular and baguette-cut diamonds; estimated total diamond weight: 17.50 carats; mounted in platinum; length: 2in.

Accompanied by AGL report # CS 1079561, dated October 27, 2016, stating the emerald as: Colombian origin, indications of insignificant (traditional) clarity enhancement.

Lot 177. An Art Deco Colombian emerald and diamond bracelet, Tiffany & Co., circa 1925. Estimate US$ 75,000 - 85,000 (€71,000 - 80,000). Photo: Bonhams.

centering a squared sugarloaf emerald cabochon, weighing approximately 10.50 carats, between a graduated line of old European-cut diamonds, with a calibré-cut emerald border; signed Tiffany & Co., no.180; estimated total diamond weight: 22.00 carats; mounted in platinum; diameter: 2 1/8in.

Accompanied by AGL report # CS 1079562, dated October 27, 2016, stating the emerald as: Colombian origin, indications of minor (traditional) clarity enhancement.

Lot 24. A diamond bracelet, French. Estimate US$ 25,000 - 35,000 (€24,000 - 33,000). Photo: Bonhams.

a flexible band of honeycomb design, set with old European and round brilliant-cut diamonds; unsigned, with maker's mark and French assay mark; estimated total diamond weight: 30.00 carats; mounted in platinum and 18k white gold; length: 7 1/4in.