Collection of thirty-eight unmounted diamonds

The thirty-eight diamonds of various tints, ranging from 0.20 to 6.83 carats.

Accompanied by fifteen GIA reports and twenty-three photocopies of GIA reports, as follows: a photocopy of GIA report 687761, dated 25 February 1975, stating that the marquise-shaped diamond weighing 6.83 carats and measuring approximately 19.45 x 9.60 x 6.07mm, is Fancy Yellow Green, Natural Colour; GIA report no. 6173433328, stating that the pear-shaped diamond weighing 6.74 carats and measuring 16.17 x 10.25 x 6.56mm, is Fancy Vivid Orange-Yellow, Natural Colour, I1 Clarity; a photocopy of GIA report 153456, dated 10 July 1978, stating that the round brilliant-cut diamond weighing 6.23 carats and measuring approximately 11.20 x 11.81 x 6.84mm, is Fancy Greenish-Yellow, Natural Colour; GIA report no. 6173433359, stating that the step-cut diamond weighing 3.28 carats and measuring 9.18 x 7.73 x 5.42mm, is Fancy Intense Yellow, Natural Colour, VS1 Clarity; GIA report no. 5171433351, stating that the marquise-shaped diamond weighing 2.78 carats and measuring 12.67 x 7.51 x 4.83mm, is Fancy Pink, Natural Colour, I1 Clarity; GIA report no. 1176433360, stating that the brilliant-cut diamond weighing 2.34 carats and measuring 8.62 x 8.95 x 5.10mm, is Fancy Deep Yellow-Orange, Natural Colour, VS2 Clarity; a photocopy of GIA report no. 101698, dated 18 March 1976, stating that the round brilliant-cut diamond weighing 2.20 carats and measuring approximately 8.65 x 8.75 x 5.26mm, is Fancy Yellow-Green, Natural Colour; a photocopy of GIA report no. 101695, dated 18 March 1976, stating that the oval brilliant-cut diamond weighing 2.09 carats and measuring approximately 8.50 x 6.45 x 5.40mm, is Fancy Orange-Yellow, Natural Colour; a photocopy of GIA report no. 677122, dated 1 March 1974, stating that the round brilliant-cut diamond weighing 1.85 carats and measuring approximately 8.30 x 8.40 x 4.45mm, is Fancy Yellow, Natural Colour; GIA report no. 2171433337, stating that the brilliant-cut diamond weighing 1.46 carats and measuring 7.58 x 7.71 x 4.15mm, is Fancy Deep Brownish Orange, Natural Colour, SI2 Clarity; a photocopy of GIA report no. 101733, dated 18 March 1976, stating that the pear-shaped diamond weighing 1.22 carats and measuring approximately 8.70 x 6.26 x 3.67mm, is Fancy Orange, Natural Colour; a photocopy of GIA report no. 101696, dated 18 March 1976, stating that the round brilliant-cut diamond weighing 1.21 carats and measuring approximately 6.55 x 6.64 x 4.27mm, is Fancy Brownish-Yellow, Natural Colour; a photocopy of GIA report no. 677189, dated 1 March 1974, stating that the cushion octagon emerald-cut diamond weighing 1.19 carats and measuring approximately 6.45 x 5.71 x 3.85mm, is Fancy Yellow, Natural Colour; a photocopy of GIA report no. 101732, dated 18 March 1976, stating that the triangle brilliant-cut diamond weighing 1.18 carats and measuring approximately 6.87 x 7.03 x 4.40mm, is Fancy Orange-Brown, Natural Colour; a photocopy of the receipt duplicate for GIA report no. 677039, dated 1 March 1974, stating that the round brilliant-cut diamond weighing 1.12 carats and measuring approximately 6.57 x 6.78 x 4.12mm, is Fancy Yellow, Natural Colour; a photocopy of GIA report no. 1937458, dated 31 May 1988, stating that the old European brilliant-cut diamond weighing 1.13 carats and measuring approximately 6.28 x 6.47 x 4.15mm, is Fancy Yellow-Brown, Natural Colour; GIA report no. 2171433377, stating that the old European brilliant-cut diamond weighing 1.09 carats and measuring 6.34 x 6.49 x 4.39mm, is Fancy Intense Blue, Natural Colour, VS2 Clarity; a photocopy of GIA report no. 101740, dated 18 March 1976, stating that the pear-shaped diamond weighing 1.05 carats and measuring approximately 7.74 x 5.77 x 3.82mm, is Fancy Orange Yellow, Natural Colour; GIA report no. 2175433310, stating that the brilliant-cut diamond weighing 1.04 carats and measuring 7.08 x 7.17 x 3.13mm, is Fancy Intense Pink, Natural Colour, SI1 Clarity; a photocopy of GIA report no. 677084, dated 28 February 1974, stating that the round brilliant-cut diamond weighing 1.04 carats and measuring approximately 6.50 x 6.61 x 3.88mm, is Fancy Yellow, Natural Colour; a photocopy of GIA report no. 677088, dated 28 February 1974, stating that the round brilliant-cut diamond weighing 1.01 carats and measuring approximately 6.86 x 7.01 x 3.38mm, is of greenish-yellow tint, Natural Colour; a photocopy of GIA report no. 677089, dated 28 February 1974, stating that the cushion emerald-cut diamond weighing 0.98 carat and measuring approximately 5.93 x 4.79 x 3.80mm, is Fancy Yellow, Natural Colour; a photocopy of GIA report no. 677185, dated 1 March 1974, stating that the round brilliant-cut diamond weighing 0.86 carat and measuring approximately 5.90 x 6.12 x 3.69mm, is of brownish yellow tint, Natural Colour; GIA report no. 1176433366, stating that the old mine brilliant-cut diamond weighing 0.85 carat and measuring 5.88 x 5.83 x 3.53mm, is Fancy Deep Grayish Yellowish Green, Artificially Irradiated, SI2 Clarity; GIA report no. 2175433378, stating that the brilliant-cut diamond weighing 0.85 carat and measuring 5.95 x 6.04 x 3.89mm, is Fancy Dark Gray-Violet, Natural Colour, VVS2 Clarity; a photocopy of GIA report no. 677095, dated 28 February 1974, stating that the round brilliant-cut diamond weighing 0.81 carat and measuring approximately 6.22 x 6.31 x 3.23mm, is Fancy Yellow, Natural Colour; GIA report no. 6173433375, stating that the brilliant-cut diamond weighing 0.81 carat and measuring 5.90 x 6.00 x 3.77mm, is Fancy Light Gray-Blue, Natural Colour, VVS2 Clarity; a photocopy of GIA report no. 677092, dated 28 February 1974, stating that the oval brilliant-cut diamond weighing 0.80 carat and measuring approximately 5.70 x 6.14 x 3.46mm, is of brownish red tint, Natural Colour; a photocopy of GIA report no. 677093, dated 28 February 1974, stating that the round brilliant-cut diamond weighing 0.74 carat and measuring approximately 6.63 x 6.73 x 3.63mm, is Fancy Orange, Natural Colour; a photocopy of GIA report no. 677187, dated 1 March 1974, stating that the old European cut diamond weighing 0.73 carat and measuring approximately 5.10 x 5.42 x 3.82mm, is Fancy Greenish Yellow, Natural Colour; a photocopy of GIA report no. 677085, dated 28 February 1974, stating that the oval brilliant-cut diamond weighing 0.70 carat and measuring approximately 5.22 x 5.67 x 3.54mm, is of brownish-red tint, Natural Colour; a photocopy of GIA report no. 677087, dated 28 February 1974, stating that the round brilliant-cut diamond weighing 0.58 carat and measuring approximately 5.37 x 5.54 x 3.17mm, is of light yellowish green tint, Natural Colour; GIA report no. 2173433376, stating that the brilliant-cut diamond weighing 0.57 carat and measuring 5.37 x 5.45 x 2.90mm, is Fancy Deep Blue, Natural Colour, SI2 Clarity; GIA report no. 1172433374, stating that the brilliant-cut diamond weighing 0.48 carat and measuring 4.76 x 4.90 x 3.14mm, is Fancy Intense Pink, Natural Colour, SI2 Clarity; GIA report no. 1172433339, stating that the brilliant-cut diamond weighing 0.45 carat and measuring 4.96 x 5.04 x 2.92mm, is Fancy Vivid Yellowish Green, Artificially Irradiated, VS1 Clarity; a photocopy of GIA report no. 1937459, dated 1 June 1988, stating that the round brilliant-cut diamond weighing 0.41 carat and measuring approximately 4.77 x 4.86 x 2.83mm, is Fancy Brown, Natural Colour; GIA report no. 2175433371, stating that the brilliant-cut diamond weighing 0.35 carat and measuring 4.46 x 4.55 x 2.79mm, is Fancy Deep Green-Blue, Artificially Irradiated, SI2 Clarity; GIA report no. 2171433372, stating that the brilliant-cut diamond weighing 0.20 carat and measuring 3.89 x 3.99 x 2.19mm, is Fancy Intense Green, Natural Colour, VS2 Clarity. Please note that the certificates might require updates. For further details on the diamonds, please refer to the GIA reports.
"In response to your inquiry, we are pleased to provide you with a general report of the condition of the property described above. Please note that colour, clarity and weight of gemstones are statements of opinion only and not statements of fact by Sotheby's. We do not guarantee, and are not responsible for any certificate from a gemological laboratory that may accompany the property. We do not guarantee that watches are in working order. Prospective buyers should inspect each lot to satisfy themselves as to condition and must understand that any statement made by Sotheby's is merely a subjective, qualified opinion. Prospective buyers should also refer to refer to any Important Notices regarding this sale, which are printed in the Sale Catalogue, in particular to the Notice regarding the treatment and condition of gemstones and to the Notice regarding import of Burmese jadeite and rubies into the US.
NOTWITHSTANDING THIS REPORT OR ANY DISCUSSIONS CONCERNING A LOT, ALL LOTS ARE OFFERED AND SOLD "AS IS" IN ACCORDANCE WITH THE CONDITIONS OF BUSINESS PRINTED IN THE SALE CATALOGUE."

THE SPECTRUM COLLECTION

Mr. Vahram Gumuchian, a gem dealer of Armenian origin, moved to Belgium in the 1920s to pursue his career. His son André, following his father's advice, created trading offices in New York, Antwerp and Geneva. It was under André's leadership that the Gumuchian company earned a reputation for their coloured diamonds, of which he was fascinated. Assembled over a period of sixty-five years by three generations of the family, a significant collection of forty-one coloured diamonds was created: 'The Spectrum Collection'.

At the time owned by A.V. Gumuchian, Inc. from New York and its parent company A.V. Gumuchdjian S.A from Antwerp, the Spectrum Collection was exhibited in the American Museum of Natural History at the opening of its Gem Hall in May 1979, until 1986. In 1987, it became the property of renowned Belgian jeweller Leysen, who created the wooden display case that has accompanied the collection ever since. It changed ownership again to join the jewels of a private collector.

According to the Gemological Institute of America, only one in 10,000 diamonds is of fancy colour. Much rarer than colourless diamonds, they have represented a small percentage of the global diamond trade, and were mostly sought after by collectors. However, with an increasing availability and efforts to raise public awareness along with record-breaking sales at auction, their popularity has been expanding for the past few decades and famous jewellers have started using them in their creations.

The most important sources of fancy coloured diamonds are India, South Africa and Australia, whose Argyle mines are known to produce most of the world's pink diamonds. Of all the fancy coloured diamonds, the rarest are those of red tint, followed by blue, green, pink, orange and finally yellow. The Spectrum Collection, with diamonds weighing from 0.20 to 6.86 carats, for a total weight of 63.85 carats, includes stones of many of these rare tints, and is one of the world's finest collection of coloured diamonds.