Significant Ceylon/Sri Lanka Blue Sapphires that appeared at public auctions

    Indeed Rashid ! Heat treated blue sapphires have a low price-per-carat value than untreated natural blue sapphires. Both in terms of whole stone price and price-per-carat value, the 12.00-carat, cushion-shaped, heat treated Ceylon blue sapphire has the lowest value as the following lists clearly demonstrate.


    The price-per-carat values of the Ceylon sapphires highlighted by Mikegem seem to indicate the quality of these sapphires.


    Lot 1796 with the highest ppc-value of US$14,356 seems to have the highest quality, with a saturated, evenly distributed violet-blue hue and a medium dark tone, the look-alike of most Kashmir sapphires. Had the origin of this sapphire been conclusively proved to be Kashmir, its ppc-value would have shot up to over US$100,000.


    Lot 1560 has the lowest ppc value of US$2,550. The ridiculously low ppc-value of this sapphire is undoubtedly due to Lab confirmation that the stone had been subjected to heat enhancement.


    Lot 1622, despite the fact the sapphire is a natural Ceylon stone with no evidence of heat enhancement, also had a low ppc-value of US$3,572. This was probably due to the dark-blue hue and the very-dark tone of the sapphire.


    Lot 1779 on the other hand had a ppc-value of US$5,284 the price of an average-quality Ceylon blue sapphire. These sapphires have a slightly lesser dark hue and tone than lot 1622.


    Incorporating the sapphires highlighted by gemlite and Mikegem in the List of Ceylon blue sapphires that appeared at public auctions arranged in descending order of whole stone prices, we have the following revised list :-


    1) 102.61-carat, cushion-cut Ceylon blue sapphire - USD 4,203,118
    2) 43.27-carat, pear-shaped Ceylon blue sapphire - USD 545,243
    3) 28.21-carat, oval-cut Ceylon blue sapphire -USD 344,309
    4) 13.28-carat, cushion-shaped, Ceylon blue sapphire - USD 190,654
    5) 30.52-carat, rectangular step-cut Ceylon blue sapphire - USD 168,492
    6) 29.30-carat, circular-cut, Ceylon blue sapphire - USD 104,667
    7) 10.206-carat and 8.628-carat pear-shaped Ceylon blue sapphires, set as centerpiece of pair of sapphire and diamond cluster rings - USD 101,214
    8) 13.61-carat, cushion-cut, Ceylon blue sapphire -USD 92,643
    9) 8.90-carat and 7.86-carat matching, cushion-shaped, Ceylon blue sapphires - USD 88,564
    10) 15.32-carat, oval-cut, Ceylon blue sapphire - USD 74,932
    11) 22.99-carat, oval-cut Ceylon blue sapphire - USD 74,932
    12) 10.22-carat, oval-cut, Ceylon blue sapphire - USD 35,423
    13) 12.00-carat, cushion-shaped, heat-treated Ceylon blue sapphire - USD 30,595


    The same sapphires above arranged in descending order of price-per-carat values is given below :-


    1) 102.61-carat, cushion-cut Ceylon blue sapphire - ppc value USD 40,962
    2) 13.28-carat, cushion-cut, Ceylon blue sapphire - ppc value USD 14,356
    3) 43.27-carat, pear-shaped, Ceylon blue sapphire - ppc value USD 12,600
    4) 28.21-carat, oval-cut Ceylon blue sapphire - ppc value USD 12,205
    5) 13.61-carat, cushion-cut, Ceylon blue sapphire - ppc value 6,807
    6) 30.52-carat, rectangular step-cut Ceylon blue sapphire - ppc value USD 5,520
    7) 10.2-carat and 8.6-carat, matching pear-shaped, Ceylon blue sapphires - ppc value USD 5,383
    8) 8.90-carat and 7.86-carat matching cushion-cut, Ceylon blue sapphires - ppc value 5,284
    9) 15.32 carat, oval-cut, Ceylon blue sapphire - ppc value USD 4,891
    10) 29.30-carat, circular-cut, Ceylon blue sapphire - ppc value USD 3,572
    11) 10.22 carat, oval-cut, Ceylon blue sapphire - ppc value USD 3,466
    12) 22.99 carat, oval-cut, Ceylon blue sapphire - ppc value USD 3,259
    13) 12.00-carart, cushion-shaped, heat-treated Ceylon blue sapphire - ppc value USD 2,550


    In both lists above the heat-treated Ceylon blue sapphire occupies the last position.

    Two significant Sri Lanka sapphire lots appeared at Christie's New York, Magnificent Jewels Sale, held on October 16, 2007. These are Lot 165 and Lot 273.
    Lot 165 is titled - An Important Sapphire And Diamond Ring and sold for US$241,000 within the presale estimate of US$200,000 - 300,000. The ring made of platinum was set with a 28.28-carat, cushion-cut, Ceylon blue sapphire with pave-set diamond shoulders. An AGTA lab report stated that the probable geographic origin of the sapphire is Sri Lanka, with no indication of heating. The ppc-value of the sapphire works out to US$8,522


    Lot 273 titled - An Impressive Sapphire And Diamond Ring, by Bulgari - was sold for US$337,000 within the presale estimate of US$300,000 - 500,000 and slightly above the lower estimate.
    The platinum ring designed by Bulgari was set with a 71.54-carat, cushion-cut, Ceylon sapphire with a pave-set diamond shoulders. An AGTA lab report stated that probable geographic origin of the stone is Sri Lanka, with no indications of heating.
    A second lab report by AGL certified the country-of-origin of the stone as Ceylon, with no indications of heating. The ppc-value of this sapphire works out to US$4,710.

    Sotheby's Geneva Magnificent Jewels Sale held on November 13, 2013 had six Sri Lanka blue sapphire lots on offer - These lots were Lot 55, Lot 184, Lot 187, Lot 232, Lot 247 and Lot 258. Out of these, the first four lots 55, 184, 187, and 232 have already been considered by Johnruby in his update of May 4, 2014. The remaining two lots, 247 and 258 are considered below :-


    Lot 247, a Sapphire and Diamond Ring from the collection of a member of the Princely House of Zu Sayn-Wittgenstein, was set with a 49.47-carat, cut-cornered rectangular step-cut, Ceylon blue sapphire as centerpiece and the shoulders set with baguette-cut diamonds. The lot was accompanied by an SSEF report certifying the Ceylon origin of the stone with no indications of heating. The lot sold for USD 410,896 which was 3 times the lower estimate of USD 136,239 and twice the upper estimate of USD 201,633. The ppc value of the stone works out to USD 8,306.


    Another lot that incorporated a modified pear-shaped Ceylon blue sapphire weighing 9.18 carats and a similarly shaped brilliant-cut diamond weighing 4.93 carats in a "Toi et Moi" engagement ring, the shoulders set with baguette-cut diamonds, was Lot 258. Two GIA reports accomanied the diamond, one certifying the Ceylon origin of the sapphire, without heat enhancement and the other stating that the diamond is F-color and VS2 Clarity. A pre-sale estimate of USD 70,844 - 79,563 was placed on the lot, which sold for USD 115,803 which is almost 1.5 times the upper estimate.

    The images of the two sapphires uploaded by shah - the 28.28-carat, cushion-cut, Ceylon sapphire and the 71.54-carat, cushion-cut, Ceylon sapphire - clearly show the violet-blue color of these sapphires - which is normally characteristic of Kashmir sapphires, but also found in blue sapphires originating from certain regions of Sri Lanka, such as Elahera and Rakwana, which some gem laboratories had mistakenly identified as Kashmir sapphires, when they were first discovered. The ideal hue, tone and saturation of these blue sapphires, their perfect cut and eye-clean clarity, would have given these sapphires a very high ppc-value, had the origin of the stones been certified as Kashmir. However, since the origin of the stones were determined to be Sri Lanka, the two sapphires had registered only moderate ppc-values of US$8,522 and US$4,710.

    The images of 49.47-carat, cut-cornered rectangular step-cut Ceylon blue sapphire and the 9.18-carat modified pear-shaped Ceylon blue sapphire uploaded by Peter, appear to show the characteristic hue, tone and saturation of Ceylon blue sapphires, which are generally lighter and brighter than Kashmir and Burma sapphires, and possess a saturated, evenly distributed, medium blue color, with good transparency and clarity. The clarity of the 9.18-carat Ceylon blue sapphire is excellent, but the 49.47-carat, rectangular step-cut Ceylon blue sapphire appears to be slightly included.


    However, what puzzles me most are the weights of the modified pear-shaped Ceylon blue sapphire and almost similar shaped, slightly smaller diamond in the "Toi et Moi" ring. While the Ceylon blue sapphire weighs 9.18 carats, the almost similar shaped but slightly smaller, colorless diamond weighs only 4.93 carats. In otherwords, if we take a blue sapphire and a diamond of similar shape and size, the blue sapphire has a weight greater than the diamond. What is the possible explanation for this ?

    Thanks AnitaP and rashid for your updates. With regards to the question raised by rashid, if a blue sapphire and diamond of equal volumes are considered, the blue sapphire has a greater weight than the diamond. This is clearly related to the difference in the densities/specific gravities of sapphires (corundum) and diamond. The density of sapphire is greater than the density of diamond. While the density/specific gravity of sapphire (corundum) is 4.0-4.1 gm/cm³, the density of diamond is 3.51 gm/cm.³ In otherwords, while 1.00 cm³ of sapphire weighs 4.0 to 4.1 gm, 1.00 cm³ of diamond weighs only 3.51 gm. Hence, while x cm³ of sapphire weighs 4.0x to 4.1x gm; x cm³ of diamond weighs only 3.51x gm. Thus, equal volumes of sapphire and diamond have slightly different weights, the sapphire weighing more than the diamond.

    Conversely, if we take equal weights of sapphire and diamond (M gm), the sapphire will have a slightly lesser volume than the diamond. In other words, the sapphire will be slightly smaller in size than the diamond. Volume= Mass/density. Volume of sapphire = M/4.1; Volume of diamond = M/3.51.

    M/4.1 < M/3.51
    ie. Volume of sapphire is less than volume of diamond. or
    Size of sapphire is less than size of diamond.


    We can actually calculate the size of sapphire and diamond in the "Toi et Moi" ring.
    Weight of sapphire = 9.18 carats = 9.18 x 0.2 gm = 1.836 gm
    Density of sapphire = 4.1 gm/cm³
    Volume of modified pear-shaped sapphire = weight/density = 1.836/4.1 = 0.4478 cm³

    Weight of diamond = 4.93 carats = 4.93 x 0.2 gm = 0.986 gm
    Density of diamond = 3.51 gm/cm³
    Volume of pear-shaped diamond = 0.986/3.51 = 0.2810 cm³

    Hence, the volume of the sapphire is 0.1668 cm³ greater than the volume of the diamond. This difference in volume or size is clearly evident in the image.

Security & Warranty Certificate by Sectigo (Comodo) U.S.A. Point to verify.

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