Golconda D

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 :-
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Among the famous diamonds in the world, what white/colorless diamonds have a Golconda provenance?

Among the List of Famous Diamonds in the World, there are several white/colorless diamonds, that have a clear-cut Golconda provenance, having originated during the period 1560 to 1750. 1560 was the year around which diamonds were first discovered in the Kollur region of Golconda east of Hyderabad, in Andhra Pradesh India, and 1750, the year around which the Golconda diamond mines were totally depleted and abandoned. It is important to note that the ancient diamond-bearing rocks of India were scattered throughout a broad belt of ancient rocks extending nearly one thousand miles in the north-south direction along the eastern half of the country, known as the eastern Deccan region of India. The vast majority of the diamonds found were from alluvial deposits - a secondary deposit formed by the breakdown of older rocks by the forces of nature and set down in river beds. Diamond mines within this belt could be divided into five main groups :-
1) The Cuddapah Group on the Penner river known as the Chennur mines, situated on the southern bank of the Penner river, near the town of Cuddapah

2) The Nandial Group between Penner and Kistna rivers, known as the Karnul diamond mines,situated near the town of Nandial.

3) The Ellore or Golconda Group on the Kistna river, known as the Kollur or Golconda mines, situated on the lower portion of the Kistna river, and include some of the oldest and most famous of Indian diamond mines, such as the Kollur mines and Parteal mines. Diamonds were first disovered in Kollur around 1560.

4) The Sambalpur Group on the Mahanadi river in Central India, the most ancient diamond mines of India. Mahanadi river is believed to be the diamond river referred to by Ptolemy,the Alexandrian-Roman mathematician, astronomer and geographer of the 1st-2nd century A.D. However, diamonds were found only around the neighborhood of Sambalpur on a fertile plain situated between the Mahanadi and Brahmani rivers ahead of their confluence.

5) The Panna Group in Bundelkhand known as the Panna mines, the most northerly group between the Khan and Son rivers.

Strictly speaking only diamonds originating from the Ellore or Golconda Group, that include the famous Kollur and Parteal mines can be characterized as Golconda diamonds, but authorities in the West, had applied the term rather loosely, to refer to any diamond originating in any one of the five groups of mines in the eastern Deccan, as there were no significant differences in the quality and standard of the diamonds, that originated in the various groups of mines.
It is precisely because of this reason, that the Koh-i-Noor diamond with a recorded history dating back to the latter-half of the 13th-century is referred to as a Golconda diamond, even though the Golconda mines were discovered only around the mid-16th century. The Koh-i-Noor diamond most probably originated in the Sambalpur Group on the Mahanadi river in Central India, the most ancient diamond mines of India.

Now coming back to Rashid's question about white/colorless diamonds among the list of famous diamonds in the world, that have a Golconda provenance, we can give the following diamonds :-
1) The Ahmedabad Diamond - A 17th-century, D-color, antique pear-shaped diamond, with a VS-1 clarity, weighing 78.86 carats, and sold at a Christie's Geneva auction in 1995 for US $4.3 million.
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2) The Archduke Joseph Diamond - A 16th or 17th-century, rectangular cushion-cut diamond with horizontally divided pavilion main facets, a style of cutting that was distinctly Indian, D-color, SI-1 clarity but potentially internally flawless, weighing 78.54 carats,with a limpid transparency and soft luminescent quality, features that entitle a diamond to be described as "Golconda," sold at a Christie's auction in Geneva in 1993 for US $6,487,945.
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3) The Arcot Diamonds - A matching pair of antique, oval or pear-cut, colorless diamonds, matching in terms of dimensions and shape, but not in weight, one weighing 33.70 carats and the other 23.65 carats, gifted by Nawab of Arcot, Muhammad Ali Khan Wala-Jah to Queen Charlotte, wife of King George III in 1777. The following is a photograph of the Arcot diamonds suspended from a bar-brooch.
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4) The Beau Sancy Diamond - Previously described as a 34-carat, double-sided pear-shaped diamond, with unknown color and clarity grades; but now reported by GIA to be 34.98-carat modified-pear, double rose-cut diamond, K-color, faint-brown but Type IIa diamond, with a clarity grade of SI-1. A diamond of Indian origin that first appeared in Europe between 1475 and 1590, and was perhaps the first Indian diamond in Europe that was cut with symmetrical facets, by none other than the Father of modern symmetrical diamond faceting, Louis de Berquem.
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5) The Briolette of India - A 90.38-carat, D-color, briolette-cut, internally flawless, Type IIa diamond, perhaps the oldest diamond in the world, with a recorded history dating back to the period 1122-1200 A.D. even older than the famous Koh-i-Noor diamond whose recorded history begins only in 1295.
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Other white/colorless diamonds of Golconda provenance in the List of Famous Diamonds in the World are :-
6) The Idol's Eye Diamond - A 70.21-carat, D-color diamond with a slightly bluish-tinge, characteristic of Golconda diamonds, and a shape/cut lying somewhere between an old-mine cut and a triangular brilliant.
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7) Indore Pears Diamonds - A pair of pear-shaped, Type IIa colorless diamonds, with E-color grading and VVS-2 clarity, and weights of 46.39 and 44.14 carats
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The Koh-i-Noor Diamond - Originally a 186-carat, Indian rose-cut diamond, but in 1852 re-cut by the British into an oval, stellar brilliant-cut diamond with 66 facets and a reduced weight of only 105.6 carats and dimensions of 36.00 x 31.90 x 13.04 mm, subsequently set on the Maltese Cross of Queen Mother's Crown.
Images below i) Tavernier's illustration of the original Kohinoor Diamond ii) The recut oval stellar brilliant Kohinoor Diamond.
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Apart from the eight Golconda diamonds so far discussed, there are some other diamonds in this list.

9) The Nepal Diamond - A 79.50-carat, pear-shaped, antique brilliant, a Type IIa colorless Golconda diamond, of unknown color and clarity grades, a valued possession of several rulers of the Royal house of Nepal, eventually purchased by Harry Winston and slightly re-cut to 79.41 carats and set as the centerpiece of a pendant/brooch combination.
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10) The Orlov Diamond - A 189.62-carat white Golconda diamond, with the characteristic faint bluish-tinge, dimensions of 47.6 x 34.92 x 31.75 mm and an antique Indian rose-cut, presented by Count Grigory Grigoryevich Orlov to Empress Catherine the Great (1762-96), who got it mounted on the Imperial Scepter, in which setting it is preserved up to this day, among the treasures of the Kremlin Diamond Fund.
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11) The Regent Diamond - A 140.64-carat, cushion-shaped, internally flawless stone, with a D-color grading, but having a slightly bluish tinge, characteristic of stones originating from the Golconda mines. The cut of the diamond is a stellar brilliant-cut with eight needle-like facets on the pavilion of the stone, pointing outwards from the culet facet.
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12) The Great Sancy Diamond - A 55.23-carat shield-shaped stone, without a pavilion; also one of the first large diamonds to be cut with symmetrical facets like the Beau Sancy; almost colorless Golconda diamond, with a very faint, pale, greenish-yellow tint; the most celebrated diamond in history, having passed through more countries, and affected more royal families than any other diamond in history.
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13) Spoonmaker's Diamond - An 86-carat, antique pear-cut, Type IIa, D-color, Golconda diamond set as the centerpiece of a brooch/pendant setting, surrounded by two rows of 49 old mine-cut diamonds, a star exhibit at the Topkapi Museum, Istanbul.
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14) Star of the East Diamond - A 94.80-carat, antique pear-cut, Type IIa, D-color Golconda stone, of unknown clarity grade, mounted as a pendant to a necklace, below a hexagonal emerald of 34 carats and a pearl of 32 grains. Part of the collection of jewels of Sultan Abdul Hamid II (1876-1909) of Turkey.
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15) The Taj-i-Mah Diamond - A 115.06-carat, Type IIa colorless Golconda diamond, with an old Moghul-cut (Indian rose-cut), and dimensions of 32.0 x 24.3 x 14.7 mm; part of the Iranian Crown Jewels, preserved in the Museum of the Treasury of National Iranian Jewels in the Central Bank of Iran,Teheran.
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Dear Rashid, I do hope I have answered your question to your satisfaction. I have dealt with only about 15 main diamonds, that have a clear-cut Indian/Golconda provenance, and fall under the category colorless/white, but not necessarily D-color, and some having the characteristic faint blue afterglow. There are of course other Golconda diamonds that have colors besides white/colorless, such as Type IIa pink diamonds and Type IIb blue diamonds, which I hope could be discussed when the need arises.

Thanks for taking all the trouble in giving us an almost total and exhaustive reply on white/colorless diamonds of Golconda origin. The images you posted were of excellent quality, and helped to drive home the point you were trying to make, on the superior qualities of these historic diamonds. I can now appreciate the fact that India was indeed a treasure-trove of these priceless diamonds for over two millennia, catering to the ancient kingdoms and monarchies spread across the world.