This was a question on the Golconda-D Diamond, a C2 comment which was transferred to this page.
Thanks for your comments Mr. Richard Wise, on our webpage titled the Golconda-D diamond, and the question raised by you about its grading and fluorescence rating. The Golconda-D diamond reported to have been purchased by Laurence Graff from its previous owners in Bombay, and slightly re-cut and polished to a 47.29-carat, internally flawless, round brilliant-cut, D-color diamond, is a product of the renowned House of Graff, and is listed among the 41 Important Gemstones, that had passed through their workshops, and had been either sold to their customers or still retained by the company. As a matter of policy all Graff diamonds sold by the company are accompanied by a GIA certificate, which verifies the cut,clarity, color and carat-weight of each diamond. Besides this, all Graff diamonds are also laser-inscribed on the girdle with the Graff Logo and the GIA identification number. Hence we can assume, that the same standards would have been applied to the Golconda-D diamond as well, and the diamond would certainly have undergone testing by the GIA. Diamond Grading Reports issued by the GIA also includes a section on fluorescence rating, that gives the strength and color of the diamond when viewed under long-wave ultraviolet light. Unfortunately, we are not aware of the fluorescence rating of this diamond, and most websites only give prominence to the 4Cs of the diamond. However, if as it is claimed,the diamond is a Golconda diamond, in all probability the fluorescence rating should be “none” which represents a range of fluorescence from indiscernible to very faint.
What are the criteria applied to decide whether a given Type IIa, D-color diamond also known as “top color” diamond, qualify to be categorized as a “Golconda” diamond?
According to gemologist Richard W. Wise for a Type IIa, D-color diamond to be characterized as a Golconda diamond, it should possess at least three visual characteristics :-1) A high degree of transparency, known as “limpidity” by Ian Balfour, “Super Crystal” by Richard Wise, and “Super-D” by some dealers.2) An ultra-whiteness, variously referred to in superlatives as “whiter than white,” “brighter than bright,” “diamond of the purest water.” “more colorless than colorless,” "purest of the pure’ etc. 3)The appearance of a blue afterglow in direct sunlight, despite the fact that most of these Golconda diamonds do not show any discernible fluorescence either in short or long-wave ultra-violet light. Such diamonds in the past were known as blue-white diamonds. However, the term blue-white today is used to describe diamonds that exhibit blue ultraviolet fluorescence. The “Regent diamond” is an example of a true legendary blue-white diamond.The Golconda diamond mines were almost totally exhausted by the mid 18th-century, around 1750s. However, Type IIa diamonds originating from other sources, such as Brazil, South Africa etc. may also be characterized as “Golconda” if they possess the above three visual characteristics.The following image is that of the legendary, true, blue-white, Golconda diamond, the Regent diamond :-[attachment=87]
The criteria laid down by the Gubelin Gem Lab based in Lucerne, Switzerland, to characterize a diamond as Golconda is more stringent than other authorities. These characteristics are :-1) The diamond should be Type IIa.2) The clarity of the diamond should be flawless, internally flawless or potentially internally flawless.3) The diamond should have a D-color grade, absolutely colorless with a high degree transparency.4) Genuine Golconda diamonds must have an antique flair, exhibiting features typical for antique cuts, before 1920, the year the modern brilliant-cut was introduced.5) The diamonds should have antique shapes and cuts, prevalent before the introduction of the modern round brilliant-cut in 1920, such as cushion shape, old-pear shape, oval shape, marquise shapes with rounded ends, and baroque shape and cuts such as the old-European cut and the old-mine cut. Modern cut diamonds such as round brilliant stones cannot qualify for Golconda.The following is a photograph of a baroque brilliant-cut/old-European cut Golconda diamond from the Gubelin Gemlab website :-[attachment=88]
The Gubelin Gem Lab criteria for Golconda diamonds do not mention anything about the blue afterglow in direct sunlight observed in many Golconda diamonds, even though such diamonds do not show any fluorescence.
Thanks Joan for making this important observation. However, the stringent Gubelin criteria for clarity, color, transparency, cut and shape, will automatically ensure that only genuine diamonds will qualify for Golconda classification, and this will undoubtedly include the blue-white Golconda diamonds. Nevertheless, the appearance of a blue afterglow in direct sunlight which is characteristic of most Golconda diamonds, can be used as a confirmatory feature, once a diamond has been identified positively as a Golconda under the Gubelin criteria.
I stumbled upon this pair of rare magnificent, old-mine cut, pear-shaped Golconda diamonds, with ear pendant mounts weighing 27.72 carats and 33.83 carats, that appeared at the Christie’s Geneva Magnificent Jewels Sale 1327, held at Hotel Richemond on May 19, 2005. The pair of diamonds sold for US $4.07 million, above the upper pre-sale estimate of US $3.95 million.
Thanks Peter, for your post. Your contribution is timely and relevant to our discussion.
Hi Peter, thanks for your update. I am sure there must have been a lab report accompanying these diamonds. Can you please give us more details.
In fact there had been two lab reports accompanying this lot - one from the GIA and the other from the Gübelin Gem Lab. The GIA reports, nos. 14287350 and 14287352 dated February 23, 2005, pertaining to the two diamonds state, that the diamonds are old-mine cut, pear-shaped, D-color, VS1 clarity but potentially flawless. the GGL reports, nos. 0503120 and 0503119 dated 16 March 2005, state that the diamonds are Type IIa, D-color, VS1 clarity but potentially flawless, possess an antique cutting style rarely encountered in the gem trade today.The lot description further states- "The diamonds display a colour and degree of transparency which are particular to these unique gemstones. Diamonds of this type, exhibiting an antique cutting style as well as a fine quality, are very rare and will most certainly evoke references to the historic term of “Golconda”'.
I was able to locate the Christie’s Lot Finder pertaining to the sale stumbled upon by Peter. The pair of magnificent Golconda diamonds referred to by Peter, was Lot No. 446 in this Christie’s Magnificent Jewels Sale held in Geneva on May 19, 2005. A well written account on “Golconda Diamonds,” their unique characteristics and what sets them apart from other diamonds that was published as a Pre-Lot Text is fully reproduced below for the benefit of our readers.
The above account on the famous Golconda diamonds emphasizes the superior transparency and luminosity of these diamonds. The degree of transparency of these diamonds, not to be confused with clarity or being free from flaws, allows the free unimpeded passage of light, as if it were passing through a vacuum. The surface luster is soft and gentle, but luminous and striking. The writer compares the degree of transparency and luminous quality of Golconda diamonds, with diamonds from other countries such as South Africa, Russia, Canada and Australia and says such a degree is rarely seen in stones from these countries, a superior quality variously referred to as soft, limpid, watery or pure, which other writers had previously described in superlatives, such as “whiter than white,” “brighter than bright,” “more colorless than colorless,” “purest of the pure” and “diamonds of the purest water.”
Original Golconda diamonds are now extremely rare, and occur today only in museum collections or the collections of royalty and rich connoisseurs of diamonds. However, occasionally such diamonds come up for sale at auctions of renowned auction houses, such as Christie’s, Sotheby’s and Bonhams, and are snapped up by diamond connoisseurs, who are prepared to pay enhanced prices for such diamonds in keeping with their rarity. It was just last year on May 31st, 2011, at the Christie’s Hong-Kong Magnificent Jewels Sale, a spectacular pair of diamond ear-pendants known as “The Imperial Cushions” incorporating two antique cushion-cut Golconda diamonds weighing 23.49 and 23.11 carats, appeared at the auctions and was sold for US $9.3 million, within the pre-sale estimate of US $7.1 million to $9.7 million.The following is a photograph of this spectacular pair of diamond ear-pendants :-[attachment=91]
Thank you Anitap for your post. You have made another valuable contribution to our discussion.
The two diamonds are similar in their cushion shapes, antique cut and their almost identical weights, although one appears to be slightly bigger than the other. What does the lab report say about these diamonds?
There were two lab reports accompanying this lot- one by the GIA and the other by the GGL.The GIA reports bearing nos. 11030047 and 11030046, and dated March 25, 2011, state that the diamonds have weights of 23.49 and 23.11 carats, with a D-color and VVS1 clarity and a working diagram indicating that the clarity is potentially flawless.The GGL reports bearing nos. 11030047 and 11030046, and dated 14 March 2011, confirm that the diamonds have weights of 23.49 and 23.11 carats, and are D-color, but the clarity slightly lower - VS1. What’s interesting are the contents of a note from the Gübelin Gemmological Laboratory that accompanied the reports, reproduced verbatim below so as not to dilute its flavor :- The diamonds possess an antique cutting style which is rarely encountered in the gem trade today. In addition, the diamonds are classified as type IIa (a chemically very pure type of natural diamond). They display a colour and degree of transparency which are particular to the finest of these unique gemstones. Diamonds of this type, exhibiting an antique cutting style as well as a superior quality, are very rare and will most certainly evoke references to the historic term of “Golconda”. In addition, the occurrence of such a matching pair of Golconda diamonds, incredibly similar in size, cut and shape, while displaying identical colour and spectroscopic characteristics, is an exceptional coincidence in itself. When placed table against table in a symmetrically opposed fashion, these two pieces seems to form a nice “dipyramidal” shape, suggesting they might originate from one large single rough crystal.Such a well-matched pair of Golconda Diamonds reaching over 23 carats in size remains an undeniable rarity.
The GGL report no doubt emphasizes the incredible similarity in size, cut, shape, color and other spectroscopic characteristics between the two diamonds to the extent of suggesting that they might have originated from one and the same, single large rough crystal as evidenced by a perfect di-pyramidal shape produced, when the two diamonds are placed against one another facing table to table.
The diamonds no doubt are original Golconda stones, and originated before the 1750s, when the Indian mines were finally abandoned. Apart from the diamonds can someone give an indication as to the period when the ear-pendants incorporating the Imperial Cushion diamonds, were produced?
The diamonds as you said are undoubtedly Golconda diamonds that originated prior to the mid-18th century, with a color and degree of transparency characteristic of these unique diamonds and an antique cutting style. However, the setting of this spectacular pair of dangling diamond ear-pendants seem to be more recent, possibly during the Belle Epoque period (1901-1915) or early Art Deco period (1920-1939). Some of the outstanding Belle Epoque features in the ear-pendants are :-1) White on white color scheme employed in the setting - white diamonds set on a white metal platinum, that enhanced the radiance of the diamonds.2) The use of platinum in the setting. Platinum was first introduced as a metal for jewelry setting in the Belle Epoque period, and replaced gold and silver as the principal metal in jewelry making.3) Dangling earrings such as drop-earrings and ear-pendants were popular during this period, that was combined with another popular jewelry item, the tiara. The ear-pendants were complementary to radical changes in women’s hair styles, with a tendency for cutting the hair short.
Early Art deco features in the ear-pendants :-1) White on white color scheme continued into the early Art Deco period, but later replaced by bold and bright color combinations, making use of rubies, emeralds and sapphires, apart from diamonds.2) The use of platinum continued into the early Art Deco period, but a cheaper alloy known as “white gold” was first introduced during this period.3) The popularity of dangling earrings and ear-pendants continued into the Art Deco period.4) The use of rectangular step-cut diamonds also known as rectilinear-cut or baguette-cut diamonds, also became popular in the Art Deco period. 5) The strongest evidence that the ear-pendants originated in the early Art Deco period, comes from certain design features used, that are also seen in similar dangling pendants designed by Cartier, during this period, such as the use of bell-shaped links pave-set with single-cut diamonds and the use of a single rectilinear-cut and circular-cut collet-set diamonds. Please refer to our webpage on Cartier’s Pair of Natural Pearl and Diamond Ear Pendants. The following is a photograph of the Cartier’s Natural Pearl and Diamond Ear Pendants :-[attachment=92]