Posts by Lareef

Well I don't think it means that. Both SSEF and AGL are internationally recognized gem testing laboratories in the world, with the latest state-of-the-art equipment at their disposal and a massive reference database on sapphires from around the world. The contradictory reports on the same blue sapphire by two recognized laboratories is a very rare occurrence and as I said earlier this comes within the failure rate or negative identification of 20%. The contradictory reports no doubt contributed to the sapphire being assigned a lower pre-sale estimate than that usually assigned to Kashmir sapphires. However, if the owner of the sapphire ring had sought a third opinion from another recognized laboratory, and if this lab too had confirmed that the sapphire was of Kashmir origin, things would have worked out in a different way.

Thanks Mikegem for your sharp observation. We have discussed this problem extensively on October 22, 2012, in reply to a question raised by one of our regular participants on this forum, AnitaP, why some renowned gem testing laboratories like the GIA do not issue Country-of-origin reports on any gemstones including sapphires. (Please refer to page 1 of this thread on Hill's Kashmir Sappire).

During that discussion it was pointed out that despite the advances in science and technology and the availability of advanced analytical methods, making use of modern tools and state-of-the-art equipment such as the Ultra Violet-Visible-Near Infrared spectrometer (UV-ViS-NIR) , the Raman spectroscope, Photo-Acoustic Spectroscopy (PAS), Fourier Transform Infrared Spectrometer (FT-IR), Energy-dispersive X-ray Fluorescence (ED-XRF), Laser-induced Breakdown Spectroscope (LIBS), Laser Ablation Inductively Coupled Plasma Mass Spectrometer (LA-ICP-MS), and the Scanning Electron Microscope (SEM), only a success rate of around 80% has been achieved in the relatively new field of Geographic Origin Determination. The geographic origin of a given sapphire is determined by collecting all relevant data on the sapphire, such as the nature of the inclusions, optical properties, growth characteristics if any, the nature and concentration of trace elements etc. and comparing it with the properties of a reference sapphire collection, in a database maintained by the Laboratory, containing a sufficiently high number of samples from commercially relevant mining areas and deposits worldwide which include reference stones from exhausted mines or deposits where production has ceased. AGL maintains one of the largest reference databases in the world, consisting data of over 10,000 samples collected from gem mines and deposits situated around the world.

However, there are factors that can complicate Geographic Origin Determination, such as :- 1) Heat treatment that can alter the chemistry of gemstones (Eg. the distinctive color zoning seen in sapphires from Andranondambo, Madagascar, becomes significantly less distinct when the stones are heated); 2) Non-uniformity of characteristics of sapphires even from different areas of the same deposit 3) Discovery of new locations bringing hitherto unknown new materials into the market; 4) the need to maintain a sample of stones that remains current. eg. data collected from one of the best sample populations of Ceylon blue sapphires 20 years ago may not be valid today, and has to be continuously updated from time to time. Since Geographic/Country-of-origin of a gemstone is based more on expert opinion than on conclusive evidence, there is a tendency for labs to differ occasionally, when issuing reports on the same sapphire. Sometimes when too many ambiguities arise, the labs may issue a tentative opinion or no opinion at all. All these difficulties come within the failure rate or negative identification of 20%.

I hope, this explains the discrepancy observed by Mikegem, that the 23.35-carat, cabochon blue sapphire is of Ceylon origin according to the Swiss Gemological Institute, but of Kashmir origin according to American Gem Laboratories. I am sure it was because of this discrepancy that the fairly large and attractive cabochon blue sapphire was assigned a pre-sale estimate within the range of values of Ceylon blue sapphires US$ 45,363 - 71,285 and sold for a slightly enhanced value of US$ 97,129 or ppc-value of only US$ 4,160.

Hence, as at October 7, 2014 the world record for price-per-carat value of Kashmir blue sapphires - US$ 236,540 - is held by the 17.16-carat, square emerald-cut, Kashmir blue sapphire, that sold at Sotheby's Hong Kong, Magnificent Jewels & Jadeite sale held on October 7, 2014.

"Hill's Kashmir Sapphire" has been one of our most popular threads, dealing mainly with all aspects of the rare Kashmir blue sapphires, the benchmark for all blue sapphires originaing from different sources across the world. The thread had registered over 50,000 views, no doubt due to the wealth of information available therein. Hence, we strongly feel that continuing with this thread, giving the latest updates on the performance of these rare blue sapphires at public auctions, is imperative not only as a source of information on blue sapphires, but also to rekindle and strengthen the international blue sapphire market. It is with this intention, that we are re-opening this thread again and as a first step, we are posting the new revised list of Kashmir blue sapphires that appeared at public auctions arranged in descending order of whole stone prices and the same list arranged again in descending order of price-per-carat values. In the revised lists we have incorporated information provided by one of our contributors - rashid - on April 13, 2015, about two record breaking Kashmir blue sapphires, that appeared at Sotheby's Hong Kong Magnificent Jewels & Jadeite Sale on October 7, 2014- Lots 1752 and 1938, whose images have already been upoaded by him.

Revised list of Kashmir blue sapphires that appeared at public auctions arranged in descending order of whole stone prices :-

1) 26.66-carat and 20.88-carat cushion-cut Richelieu Sapphires - US$ 8,358,520 - Sotheby's Geneva, November 2013- Most expensive Kashmir blue sapphires sold at an auction.
2) 28.18-carat, square emerald-cut, Kashmir blue sapphire - US$5,093,000 - Sotheby's New York, April 2014.
3) 14.84-carat and 13.47-carat cushion-cut Kashmir blue sapphires from the pair of sapphire and diamond ear-pendants - US$4,135,165 - Christie's Hong Kong May 2011.
4) 17.16-carat, square emerald-cut, Kashmir blue sapphire - US$ 4,059,031-Sotheby's Hong Kong, October 7, 2014.
5) 26.41-carat, cushion-cut, Kashmir blue sapphire - US$ 3,838,508 - Christie's Hong Kong, November 2011.
6) 19.88-carat, cushion-cut "Star of Kashmir" blue Sapphire - US$ 3,484,102 - Christie's Geneva, May 2013.
7) 42.28-carat, cushion-shaped Kashmir blue sapphire - US$ 3,458,420 - Christie's Geneva, November 2008.
21.42 carat, cushion-cut Kashmir blue sapphire - US$ 3,231,584 - Sotheby's Geneva, November 2013
9) 22.66-carat, cushion-cut Hill's Kashmir blue Sapphire - US$ $ 3,064,000 - Christie's New York, April 2007
10) 31.53-carat, cabochon-cut, Kashmir blue sapphire - US$2,658,500 - Christie's New York, April 2012
11) 20.04-carat, cushion-cut, Kashmir blue sapphire - US$ 2,614,701 - Sotheby's Hong Kong, April 2014
12) 12.00-carat, rectangular emerald-cut, Kashmir blue sapphire - US$ 2,326,078 - Sotheby's Hong Kong, October 7, 2014.
13) 21.27-carat, oval cabochon-cut, Kashmir blue sapphire - US$2,105,000 - Christie's New York, December 2013.
14) 8.91-carat, cushion-cut Kashmir blue sapphire - US$1,370,000 - Christie's New York, December 2012.
15) 10.66-carat, cushion-cut, Kashmir blue sapphire - US$1,200,398 - Christie's Hong Kong, November 2012.
16) 11.71-carat, cushion-cut, Kashmir blue sapphire - US$1,110,370 - Sotheby's Geneva, May 2013.
17) 7.68-carat, cushion-cut, Kashmir blue sapphire - US$932,657 - Sotheby's Hong Kong, April 2013.
18) 11.06-carat, cushion-cut, Kashmir blue sapphire - US$932,657 - Sotheby's Hong Kong, April 2013.
19) 9.37-carat, circular-cut, Kashmir blue sapphire - US$889,280 - Christie's Hong Kong, November 2012.
20) 12.71-carat, cushion mixed-cut, Kashmir blue sapphire - US$785,000 - Sotheby's New York, April 2014.
21) 10.40-carat, sugar-loaf cabochon-cut, Kashmir blue sapphire - US$453,446 - Sotheby's Hong Kong, April 2013.
22) 6.90-carat, cushion-cut, Kashmir blue sapphire - US$444,775 - Sotheby's Geneva, May 2013
23) 4.52-carat, cushion-cut, Kashmir blue sapphire - US$358,580 - Sotheby's Geneva, November 2013.
24) 9.68-carat, cushion-cut, Kashmir blue sapphire - US$354,249 - Woolley & Wallis auctions, May 2014
25) 5.45-carat, oval-cut, Kashmir blue sapphire - US$293,000 - Sotheby's New York, April 2014.
26) 5.48-carat, cut-cornered step-cut, Kashmir blue sapphire - US$273,567 - Sotheby's Geneva, November 2013.
27) 11.15-carat, cushion modified brilliant Kashmir blue sapphire - US$133,623 - saffronart online auction October 31, 2012.
28) 4.53-carat, oval-cut Kashmir blue sapphire - US$106,250 - Sotheby's New York, April 2014

Factor 3 above - Lots set predominantly with diamonds - appears to be the main reason why the lot was assigned a higher estimate and as expected also sold slightly above the upper estimate, even though the piece was not a signed jewel. Besides this, the use of emerald-cut emeralds as the centerpiece of each flower and the design features of the flower bracelet, might also have had an impact on the final price achieved by Lot 8.

Thanks AnitaP for your intelligent observation, and thanks Joan for your appropriate comment. I totally agree with you Joan on your comment. The blue sapphire market is indeed becoming stronger and stronger, as reflected not only by the high prices achieved by Kashmir sapphires at public auctions, but also by fine Burma and Ceylon sapphires, that are also setting new milestones at public auctions, such as the staggering US$17.7 million achieved by 392.52-carat, cushion-cut, Ceylon sapphire, "The Blue Belle of Asia Sapphire," that shattered the world record for any sapphire sold at an auction.

Of the three RBC diamonds you have mentioned Joan, The Graff Constellation diamond is yet to be sold, the Safiya diamond was sold by Graff in September 2000, to an unidentified Middle-Eastern buyer, however, the identity of the purchaser and the price of purchase was not revealed. Hence, we are left only with the Chloe diamond, which was sold at a Sotheby's Magnificent Jewels auction held in Geneva, on November 14, 2007, nearly eight years ago, for US$ 16,189,769 million (18.2 million Swiss francs). At that time the 84.37-carat Chloe diamond set several auction records, such as the largest, D-Color, flawless, round brilliant-cut diamond ever sold at an auction; the second most expensive jewel ever auctioned, the first being the 100.1-carat, D-color, pear-shaped, internally flawless, "Star of the Season" diamond which was sold in 1995, also by Sotheby's for US$16.5 million, to the Saudi-based renowned jeweler and diamond collector, Sheik Ahmed Hassan Fitaihi; the highest price-per-carat ever paid for a D-color, flawless/internally flawless diamond at an auction. The price-per-carat of the chloe diamond works out to US$191,890. In comparison the price-per-carat of the "Star of the Season" diamond was only US$ 164,835.

It is important to note that the whole stone price as well the price-per-carat of the 84.37-carat Chloe diamond was in accordance with the market values applicable in the year 2007 and hence may not be used for comparison with the price-per-carat value of diamonds sold in the year 2015. Like colored diamonds, whole stone prices as well as price-per-carat values of D-color, flawless/internally flawless diamonds, also have significantly increased particularly after the Great Recession of 2008/2009, when investors sought for safe havens to invest their money. The world record price-per-carat values of US$240,500 and US$246,710 realized respectively by the 28.86-carat and 25.32-carat D-color, flawless/internally flawless RBC diamonds is a reflection of the significant increase that took place after year 2009. Hence, the actual PPC-values of the Chloe-diamond, Safiya diamond, the Graff Constellation diamond or any other comparable RBC diamond will be known only when such a diamond appears at a public auction.

Thank you "themonetaryman" for revealing the actual aim of your original question seeking information on D-color RBC diamonds of clarity grade IF/FL above 50 carats in weight. While wishing you Good Luck in your quest for the rare diamond, I feel that we should thank you profusely for your contribution, as it has generated a discussion on various aspects of large D-color round brilliant-cut diamonds, such as there scarcity etc. I also feel that this thread on RBC diamonds would help to bring into focus all such diamonds that have performed extremely well at public auctions, including those that are less then 50 carats in weight. I invite all active contributors to our forums to help bring such RBCs to this forum and highlight their existence. Thank you !

Large D_color, Flawless or Internally Flawless round brilliant-cut diamonds are indeed very rare as diamond cutters normally tend to pick a shape/cut to suit the shape of the rough diamond, in order to minimize losses. In other words they try to maximize for both quality and quantity, rather than maximizing for quality at the expense of quantity. Hence, shapes/cuts other than round brilliant-cut are common among large diamonds, such as oval brilliant-cut, pear-shaped brilliant cuts, heart-shaped brilliant-cuts, cushion-cut, emerald-cut, asscher-cut, radiant-cut etc. As an example we can take the cutting of the 102.79-carat round brilliant-cut Graff Constellation diamond from the 478-carat "Light of Letseng" rough diamond. After a thorough study of the rough diamond by a team of engineers, gemologists and master cutters and polishers of DIAMCAD using the most advanced scanning technology, it was finally decided to cut the rough diamond into six, one main round brilliant-cut diamond and five satellite diamonds - one smaller round brilliant-cut, a heart-shaped diamond, two pear-cut diamonds and a marquise-cut diamond. The largest diamond created was the 102.79-carat, round brilliant-cut Graff Constellation diamond.The second largest was the 51.20-carat heart-shaped diamond. Four other tiny diamonds were also created from the corners of the rough stone, making a total of 9 satellite diamonds. Hence, in creating the round brilliant-cut Graff Constellation, 9 other satellite diamonds were also created at the same time.

In the case of the Light of Letseng rough diamond, the creation of 9 satellite diamonds was possible because of the high quality of the rough diamond. Thus wastage of diamond in cutting was a minimum. If the rough diamond was not of very good gem quality the creation of so many satellite diamonds would not be possible, and there would be enormous wastage in cutting the main diamond.

You have rightly mentioned the three main famous round brilliant-cut diamonds in existence, viz. the 84.37-carat Chloe Diamond, 90.97-carat Icon/Safiya Diamond and the 102.79-carat Graff Constellation Diamond. There are not many D-color, IF/FL, round brilliant-cut diamonds above 50 carats in existence. A round brilliant-cut diamond weighing 103.46 carats cut and polished by Graff and mounted on a platinum ring appeared at a Sotheby's Geneva sale held on May 13, 2014. But the diamond is N-color and SI-1 clarity and sold for US$4.8 million. However, there are quite a number of D-color, IF/FL round brilliant-cut diamonds between 10 to 50 carats that appeared at public auctions and performed significantly well.

It will be interesting to have the images of the 1st, 2nd and 3rd largest D-color, Internally- Flawless, round brilliant-cut diamonds -the Graff Constellation, the Safiya and the Chloe diamonds side by side for comparison.

Analysis of the list of ten Chrysoberyl cat's-eyes arranged in descending order of estimated values and price-per-carat values, show that the color of the gemstones have little bearing on the prices. A honey-colored Chrysoberyl cat's-eye tops the list both for estimated values and ppc values, followed by a Yellowish-green Chrysoberyl cat's-eye occupying the second place.The third place is occupied by yellowish-green gemstone and the 4th-place by a honey-colored gemstone again. Hence, there appears to be no direct relationship between the color of the gemstone and the prices achieved. Even though honey-color is considered to be top-grade, yellowish-green/lemon-yellow gemstones have also performed quite well occupying the 2nd, 3rd, 5th/6th, 7th and 8th places. Honey-colored stones occupy the 1st, 4th and 5th/6th places.

A careful study of both lists show that the single most important factor that has a bearing on the prices achieved is the weight of the gemstone. The first two gemstones on the list having the highest weights 77.01 carats and 50.40 carats have the highest estimated values and price-per-carat values in the range of USD350,00-850,000 and USD7,000-11,000 respectively. When the weight drops to 20.14 carats the estimated value also drops drastically from the range of US$350,000-550,000 to US$80,000-100,000 and the ppc values from the range of US$7,000-10,000 to US$4,000-5,000, eventhough the color of the 50.40-carat and 20.14-carat gemstones are almost identical (yellowish-green). When the weight drops below 20 carats to 19.22 carats there is further drop in the estimated value from the range of US$80,000-100,000 to US$30,000-50,000 and the ppc values from the range of USD4,000-5, 000 to USD1,500-2,500. When the weight drops to around 10 carats (9.17 and 11.24) the estimated value drops further to around USD10,000-20,000 and the ppc values to around USD1,000-2,000. The 15.55-carat yellowish-green chrysoberyl cat's-eye available for online purchase from the website multicolor.com has been priced at USD17,312. This works out to a ppc-value of USD1,113 which falls within the range of USD1,000-2,000 for 10-carat chrysoberyls.

Ridhaanya, I think we can now consider the valuation of your 9.00-carat chrysoberyl cat's-eye of excellent clarity and translucency. The three chrysoberyl cat's-eyes weighing 9.17-carats, 11.24 carats and 15.55 carats would give us an approximate guidance to the value of your gemstone. Accordingly I feel the ppc-value of your gemstone should fall within the range of USD1,000-2,000 and the whole stone price of your Chrysoberyl Cat'seye falls within the range of USD9,000-18,000.

We have considered 10 Chrysoberyl cat's-eyes in our discussion, and most of them had appeared at public auctions conducted by leading auction houses. The estimated values of these Chrysoberyl cat's-eyes give a proper valuation for these gemstones, as such evaluation was done by expert gem valuers before the auction. The actual price realized at the auction may not reflect the true value of the gmstone, as hammer prices at public auctions can be artificially inflated due to competitive bidding among rival prospective bidders or such other factors like the historic provenance of the gemstone.
Let us now list the 10 gemstones giving their estimated values and the price-per-carat of each.

1) Honey-colored Chrysoberyl cat's-eye of unknown weight - Estimate US$5,185 - $7,778; price-per-carat cannot be calculated without the weight of the stone.

Details of some Chrysoberyl cat's-eyes that appeared at the Tiancheng International Jewelry and Jadeite Spring and Autumn Auctions 2014, and Sotheby's Hong Kong Fine Jewels and Jadeite sale November 2014 are given below. These Chrysoberyl cat's-eyes have varying colors such as yellowish-green,, greenish-yellow and honey-colored/golden-yellow/golden brown color. The images of these Chrysoberyl cat's-eyes are also given.

Tiancheng International Jewellery and Jadeite Spring Auction 2014 held on June 8, 2014
1) Lot 231 - VERY IMPORTANT CAT’S-EYE CHRYSOBERYL ‘DOUBLE DRAGON’ RING - Centerpiece of the 18k yellow-gold ring carved with dragon motifs, is a 77.01-carat, round cabochon-cut, cat's-eye chrysoberyl of Sri Lanka origin, with a blend of colors producing the "milk and honey" effect. Accompanied by a GGL report certifying that the cat's-eye is of Sri Lanka origin, with no indications of heating. Estimate US$695,000 - 820,000. Lot sold for US$821,000.

Tiancheng International Jewellery and Jadeite Autumn Auction 2014 held on 7 December 2014
1) Lot 51 - CAT'S-EYE CHRYSOBERYL AND DIAMOND RING, CATHERINE SAUVAGE - Centerpiece of the 18k yellow-gold ring is a 11.24-carat, round cabochon-cut, greenish-yellow cat's-eye chrysoberyl of Sri Lanka origin. Accompanied by GRS report certifying the Sri Lanka origin of the cat's-eye with no indications of treatment. Estimate US$10,000-15,000. Lot sold at US$14,450.

2) Lot 80 - CAT'S-EYE CHRYSOBERYL AND DIAMOND RING, "THE GOLDEN GLOBE" - Centerpiece of the 18k white-gold ring is a 50.40-carat, round cabochon-cut, yellowish-green catseye chrysoberyl of Sri Lanka origin with exceptional transparency, and straight, very pronounced chatoyancy . Accompanied by three lab reports by GGL, GRS and Dunaigre certifying that the catseye is of Sri Lanka origin with no indications of heating. Estimate US$385,000 to 520,000. Lot sold at - US$456,000.

Sotheby's Hong Kong Fine Jewels and Jadeite sale November 27, 2014
1) Lot 1432 - CAT'S-EYE CHRYSOBERYL AND DIAMOND RING - Centerpiece of the 18k white-gold ring is a 9.17-carat, honey-colored cat's-eye chrysoberyl of Sri lanka origin, highlighted by a pear-shaped diamond surround. GRS reports certify the natural Sri Lanka origin of the stone with no indications of heating. Estimate USD 12,900-19,300. Lot sold for US$24,000

2) Sotheby's Hong Kong Jewels and Jadeite sale April 2011 - Lot 1749 - CAT'S-EYE CHRYSOBERYL AND DIAMOND RING. Centerpiece of the ring is a 20.14-carat, oval cabochon-cut, yellowish-green, cat's-eye chrysoberyl with an exceptional degree of transparency and well-centered, straight, and very-pronounced chatoyancy. Accompanied by GGL report certifying the natural origin of the stone. Country of origin not given. Estimate USD 87,000-100,000. Lot sold for USD 120,000. Cat's-Eye chrysoberyl photographed unmounted.