The Market for Golconda Diamonds Has Mushroomed

New York Times, March 20, 2011

HYDERABAD, INDIA — In 1663, the French explorer and renowned gem merchant Jean-Baptiste Tavernier embarked on his sixth voyage from Europe to the Orient. The epic journey led him from Paris to Persia and, finally, to the fortified city of Golconda, the seat of power of a fabled kingdom in south-central India, in what today is the state of Hyderabad.

Known to Europeans since the days of Marco Polo, Golconda was a trading center for diamonds from the Kollur Mine, the most prestigious among a group of local mines that produced, from ancient times through the end of the 19th century, history’s best-known diamonds, including the Hope, the Koh-i-Noor and the Regent.

On this journey, Tavernier was permitted to examine the Great Mogul Diamond, a colossal gem shaped like half of a hen’s egg and named after Shah Akbar, the third of India’s Mogul emperors.

The stone vanished soon after, though unconfirmed sightings of it, or smaller gems cut from it, have been reported over the centuries.

In “Travels in India,” the merchant’s 1676 memoir, he described the diamond as “a round rose in shape, very high at one side.”

“Its water is beautiful and it weighs 3191/2 ratis, which are equal to 280 of our carats, the rati being seven-eighths of our carat,” Tavernier wrote.

The reference to the stone’s “water” is lost upon most modern jewelry enthusiasts. But to the earliest gem traders, that elusive quality meant everything.

Until the advent of more sophisticated cutting techniques in the late 17th century, brilliance, or the quality of light return that allows a stone to sparkle, had little bearing on a diamond’s value. Instead, gems were prized for the purity of their crystal. The most transparent, and coveted, diamonds were known as “gems of the first water.”

François Curiel, Christie’s chief jewelry specialist, said a Golconda diamond has a quality “like water or a river going through the gem.”

Richard Wise, a gem dealer in Lenox, Massachusetts, said, “You hear them called ‘whiter than white.”’ Mr. Wise is the author of “The French Blue,” a fictional account of Tavernier’s discovery of the 116-carat blue diamond that would eventually give rise to the 45.52-carat Hope.

Connoisseurs have rediscovered the allure of these legendary gems. “In the last five years, the market for Golcondas has mushroomed,” said Rolf von Bueren, chairman of Lotus Arts de Vivre, a jewelry manufacturer in Bangkok that obtains them from a trusted supplier in New Delhi. “Like so many things in the world, what wasn’t rare 20 years ago is rare today. It’s like peeling an onion: You take off one layer and that becomes common and known, so you peel off the next layer. In diamonds, nothing surpasses Golcondas.”

What distinguishes Golcondas and their ilk from the vast majority of diamonds is their Type IIa designation, referring to gems that are devoid of nitrogen. The element, present in Type I diamonds, lends stones a slightly yellowish tinge.

“Only 2 percent of all diamonds are found in this Type II category,” said Thomas M. Moses, senior vice president of laboratory and research at the Gemological Institute of America, G.I.A.. “Because they’re so pure, they transmit UV and visible light that Type I diamonds block. They have a clear, limpid, transparent nature. They look like ice cubes.”

Which is not to suggest that Type II diamonds are always colorless. Occasionally, they are brown or pink, and still rarer are those infused with a delicate blush of blue or gray. Categorized as Type IIb, the blue gems, also nitrogen-free, owe their hue to traces of boron.

The Golconda mines have closed. But other sources of Type II diamonds are still in production. “Today, the exact same stones come from Lesotho and South Africa,” said Marvin Samuels, chief executive of Premier Gem Corp., a New York diamond supplier specializing in large, fine stones.