All That Glitters: Precious Gems
From the Print Edition:
Wayne Gretzky, Mar/Apr 97
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Skulduggery and colored gemstones are old partners. Unlike diamond mining, where the reservoir of gems is so predictable that miners know the size and shape of the stones they will find, the mining of rubies, sapphires and emeralds remains as unpredictable, and as primitive, as it has been throughout history. For the most part, precious colored stones are still mined by men standing in muddy water, working tons of silt, one bucket at a time.
Of the big three colored gemstones, ruby is by far the rarest. Yet ruby and sapphire are two sides of the same coin. They are both members of the corundum family, differing only in the minerals present at the time of formation. It is these elements that give each stone its color. To complicate the matter even further, though sapphire is synonymous with blue, particularly an intense and lively color known as cornflower blue, sapphire occurs in a rainbow of colors: gray, yellow, pale pink, orange, green, violet and brown, even colorless. All of these varieties are called fancy sapphire. Yet when corundum occurs as a red or deeply pink stone, it is called ruby. And only a trace of mineral (iron and titanium for blue sapphire, chromium for ruby) separates the two.
Sapphire and ruby are treasured not only for their beauty but their durability. They are second only to diamond, with a hardness of nine as measured by the Mohs scale, the geologist's ranking of hardness in minerals. (Rankings are strictly according to whether one mineral can scratch another.) But ruby, treasured for its intense and pure red color, is also distinguished by its rarity. You cannot just order up a five-carat, gem-quality Burma or an intense Kashmir sapphire--still considered the absolute best, though mining ended in both regions many years ago. No matter how much money is offered, even the most knowledgeable colored stone dealer with connections all over the gem world--which is to say, all over the earth--must search and search for such a rare gem. Unlike diamonds, which are available in virtually any size and quality up to 10 carats, these colored gemstones have always been in short supply, particularly in the finest qualities. When such a stone becomes available these days, it is likely to be a stone mined long ago and simply coming back on the market, often at auction. There, it can command bids from buyers all over the world. Such a stone was scheduled to appear last November at a unique all-Cartier sale organized by Antiquorum and Etude Tajan in Geneva. The stone, a 65-carat Kashmir sapphire set in a diamond and saphhire bracelet, was so desirable that it disappeared from a showcase while on view in Milan, just five days before the auction. The sapphire was of breathtaking intensity, a blue that makes most sapphires pale (or darken) by comparison. The stone, which was estimated at $2 million, is unlikely to be seen again.
Abe Nassi, a New York dealer who specializes in the big three colored stones, says, "You have to realize that fine stones are rare to begin with. Out of 1,000 Burma rubies that were mined, maybe three stones are fine." This is not a phenomenon of just our own era. He cited the Bible, where scarcity was described as "rare as pigeon blood rubies." That rather nasty term has always been the standard against which the color of ruby is judged. It is a term so frequently used one has to assume that in Burma (now known as Myanmar) and neighboring countries with gem deposits, killing pigeons is a fairly popular occurrence.
"It would take perhaps one to two years to find a five-carat gem Burma ruby--and that means the finest color, well cut, with tremendous brilliance, and at least 80 to 90 percent clean. And, an untreated stone, one that has not been heated to enhance the color," says Nassi. "You cannot find an absolutely flawless stone. It would take a lot of legwork to find it, and it would cost you about $150,000 a carat." That's $750,000 for a five-carat stone--and you would still have to wait for it to be located.
Myanmar is not the only source of ruby, although there is considerable debate about whether any other stones can match the Burma ruby for color. Ruby occurs in few places in the world. Stones from neighboring Thailand are said to be inferior in color--slightly brownish or grayish when compared to the purity of Burmese ruby. But Burmese ruby had become nearly mythical, so much a part of history as to be completely unattainable.
Then, a few years ago, the supply of ruby underwent a dramatic change. A new mining area called Mong Hsu was discovered in Myanmar. Within a short time, a ruby rush brought 100,000 diggers, panning the rivers and searching for rubies. Although exciting news, the mine did not improve the odds, or lower the price, of a five-carat gem ruby. This mine is producing small stones, under one carat when cut. But it did make it possible for jewelry manufacturers to design pieces that use multiple small stones, calibre cut, which is to say, they can be cut to exactly the same size and shape, making it possible to design jewelry lines that can be produced in quantity.
Gem dealer David Cohen, of Rafco International Gem Corp. in New York, celebrates this new mine. "There's a new excitement because rubies were so scarce. Ruby was almost becoming a collector's item; it was like a painting. The color from this new mine is true red, Burma. For a fine one-carat stone, you would pay about $4,000 to $4,500 at retail." (Gem prices do not go up in even increments as sizes increase. A five-carat stone is not five times the price of a one-carat gem; it may be 100 times more expensive because of the extreme rarity.)
The new mine still must follow the dictates of Mother Nature. According to Cheryl Kremkow of the International Colored Gemstone Association, "Mining is seasonal at Mong Hsu because of the rains." Though the stones are mined in Myanmar, dealers buy them in Thailand. The expertise in cutting the stones and trading has made the capital city, Bangkok, the capital of the ruby business as well, even though Thailand's own ruby mines have dried up or become too dangerous to work because of land mines planted along the border. Bangkok's reputation as a reliable source of gems assures dealers that the parcels of gems they select and pay for will reach them intact. That was hardly the case with Vietnam, which very recently had a brief fling at ruby mining. Whether from greed tempered by inexperience or through a stunning underestimation of the dealers' knowledge, the Vietnamese "salted" the packets with synthetics before shipping them. That romance cooled in no time and Vietnam fell off the ruby map as fast as it had appeared.
So delicate is the question of gem origin, and so entrenched is the notion that a Burmese ruby is the finest available, that other rubies, including those from Thailand, were priced lower because buyers would not pay the same price for them. This makes gem dealer Nassi see red. "Why should a ruby from anywhere be worth less than a ruby from Burma? There is such a fine line between the places, why bother to say it?" Though beauty is often in the eye of the beholder, Nassi says, "You are selling something that is hard and real; you are not selling an illusion." Referring to sapphires, he adds, "Who is the one that said Colombian or Kashmir is worth more than the other one? Some stones from Montana are as good as any Ceylon (Sri Lankan) sapphire; why should they be worth less? In my opinion, there is no stone better than a gem Burma sapphire, but everyone says Kashmir."
Going even further afield, Nassi says, "Colombian emerald is by no means better than a Zambian stone. But history never had stones from Zambia before. People stick to the old, thinking it's good. But we don't live in the past, we live in the present. We have to accept the new. The old order gives way, yielding place to the new."
The whole question of rarity is turned on its head when speaking of fine sapphires. Though valued as a gemstone for 3,000 years, and in spite of it being nearly a twin to ruby as far as mineral content is concerned, sapphire is far more available, and therefore much less expensive than ruby. But for some, there is no color so beautiful as a richly saturated, intensely blue sapphire. If you've only seen commercial qualities you may think that sapphires are inky in color, almost black. But take a look at a Kashmir sapphire--if you can find one. "Most people who are looking for a Kashmir should not even start looking," Nassi says. "It's not coming out of the ground at all, and you'd have to wait many years. If you even find one, you'll be paying about $30,000 a carat. The same is true of a Burma sapphire; for a gem five-carat stone, of excellent color, with perfect cutting and 90 percent or better clarity, you'll pay $15,000 a carat." Either stone is considerably cheaper than the gem quality ruby, because sapphires generally occur as cleaner stones.
Gem dealer Cohen notes, "A five-carat sapphire is not rare; they even come in 20-carat sizes, which ruby does not. Sri Lanka is the best source for quality [sapphires]. Kashmir is extremely rare, collectible. Kashmir only changes hands; it's not available from mining. But there are new finds now in Africa, in Tanzania and Madagascar, and some of them look comparable to the material from Sri Lanka."
If you look at a map of the world, and you mentally cut out the continent of Africa and the portion of Asia where the gem mining countries are found, you'll find they fit together quite neatly. It's not much of a stretch to believe that this was once one land mass, which explains why the geology is so similar in these distant places.
These newer finds, in southern Tanzania and on the island of Madagascar, off the East African coast, have excited dealers. "Some of them look comparable to Sri Lanka," Cohen says. A single sapphire specimen weighing 18 kilograms (nearly 40 pounds) was found in Madagascar and was sent to Bangkok. The seller was looking for a buyer who would keep the stone intact, as a specimen. Price? Make your best offer.
"The sapphire from Madagascar is of an intense and saturated blue, reminiscent of Kashmir," Kremkow of the international gemstone association says. Only small sizes have been seen but, "there is speculation that if you go down you will find larger sizes." However, she adds, "There's a political problem in Madagascar and we don't know what will happen with that deposit." The uncertainty stems from inconsistency in the government's policy on gem trading and mining, as well as in its tax laws, Kremkow says.
Sapphire mining is also booming in Australia. Production is an astounding 50 million carats of sapphire annually, most of it blue, although not the most desirable Kashmir blue. This is commercial material, not gem quality. About eight years ago there was some newly mined Kashmir sapphire available, according to Nassi, but it didn't last long--the mining conditions were simply too difficult. "There is material there, rubies and sapphires, and a little of it is still coming out," he says.
Fancy colored sapphires in a rainbow of hues are one specialty of the retail shop Reinstein/Ross of New York. By working with just one mineral, and such a durable one, they simplify the work of setting the stones--the amount of pressure the setter can apply to a stone is always the same, a considerable advantage. The many colors of sapphire enable Susan Reinstein, the designer, and Bryan Ross, the gem dealer, to please virtually every customer. Ross, who travels to Thailand every year to buy gems for the shop's designs, says, "Thailand is a crossroads. Sapphire will come in from Sri Lanka, Australia, Cambodia and from Chanthaburi, Thailand, near the Cambodia border. The market would shift on Friday afternoon from Bangkok to the new mining areas." So risky are some of the gem mining areas due to political instability that dealers survive by being up to the minute on the news. Ross recalls one visit to the region: "We were on a flight from Jaipur [India] to Bombay with a change of planes to Colombo [Sri Lanka's capital]. We rerouted our flight as soon as we got to Bombay because there was so much fighting in Colombo. Why should we risk our lives for a few sapphires?"
Perhaps the rarest fancy color sapphires are exquisite orange-pink or pinkish-orange stones named for the lotus blossom, Padparadscha. Found originally in Sri Lanka, similar colored stones have been mined in Tanzania's Umba Valley, though purists refuse to accept these somewhat brighter stones, with a more reddish-orange color, as true Padparadschas. Pads, as they are known, are extremely rare and have become collectors' items, bought up as quickly as they are found. Ross says that yellow-and-orange sapphires have also become very expensive, costing hundreds of dollars a carat. And fancy colored sapphire cabochons (a form of cut in the shape of a rounded dome) are almost impossible to find, because everything in Thailand is now being faceted. The cutting adds a little value to the stone, but while it gives the dealers a better price, it's only a matter of pennies per stone, according to Ross.
Fancy colored sapphires are rated according to the intensity of their hue: to be valuable, they should be vivid in color, and very clean and clear. Choice of color is strictly in the eye of the beholder: if you like green, or yellow, or violet, these are the stones that will catch your eye.
However, if emerald green is the color that you crave, then only an emerald will do. Of the big three colored gemstones, emeralds occupy their own category. Not nearly as hard as ruby and sapphire, emerald is a form of beryl and is rated eight on the hardness scale. The color derives from small amounts of chromium, enhanced by traces of iron. Don't attempt to find a truly clean emerald: these stones nearly always have deep inclusions, that is, tiny imperfections in the form of crystal structures within the stones. These inclusions have been given beautiful names such as "silk" and "jardin," meaning garden. Emerald's beautiful color forces people to overlook these flaws; they never bothered the Moguls of India, who loved their big emeralds no matter how included they were.
Historically, the richest source of emeralds has been South America. The Muzo mine, about 160 miles north of Bogota, Colombia, has been producing for thousands of years, give or take a few insurrections. "There is a unique geology in the mountains there," Cheryl Kremkow says. "The existing mines are along one formation. They have been blessed with such incredibly rich deposits no one has looked for more." Emerald also has its mystical sources: Sandawana emeralds, from Zimbabwe in Africa, have always found ready buyers who value them for their beauty, though they generally occur only in small sizes. Among the newer sources of emerald is Zambia, in central Africa. Zambia emerald quickly became one of the most important sources, ranking below that of Colombia for value. The deposit occurs near the copper mines, a common occurrence. These stones, as Nassi said, have had to struggle to make their way in the world simply because they originate from a new source, not from some long-established, highly esteemed mine. It would appear that newness is simply suspect in the highly secretive, closed world of gems and gem dealers.
New York City gem dealer Doug Parker of Wm. Kuhn Co. echoes Nassi's displeasure regarding gem origins. "I like beautiful stones; I buy for beauty, and I dislike the trade's emphasis on origin. I buy a lot of Zambia material; I can get clearer stones. The crystalline structure of the Zambian stones seems to be a little stronger."
The love of emerald green is so strong it overcomes emerald's inherent drawback: the fractures create weaknesses in the stones that make them susceptible to cracking. If the fracture is on the surface, emeralds are best worn as earrings or necklaces, rather than as rings or bracelets where they are far more subject to contact with hard surfaces. For the goldsmith, setting emeralds is a far more perilous task than the setting of the far tougher rubies and sapphires. The characteristic shape of emerald was the source of inspiration for the emerald cut, a simple rectangle faceted with "steps."
Emeralds are usually helped along in other ways as well. Most emeralds are oiled, which fills in the cracks and helps to stabilize the stones. This is a way of vastly improving the quality of a given stone. Such treatments are widely practiced, and are the reason that an emerald requires the most delicate of care. Emerald jewelry should not be cleaned in an ultrasonic cleaner, because the ultrasonic waves would prey on the weakness of the fractures in the stone and crack the stone into pieces, and the oil could be removed in the process, leaving you with a more fragile stone.
But emeralds are scarcely the only stones to undergo treatment. Blue sapphires are routinely heat-treated to intensify their color. Sometimes the original gem material is actually colorless, but through the application of heat, a beautiful blue sapphire may emerge. Sri Lankans are masters at this, though suspicions were raised only because they were producing so much material of such excellent color. One of the drawbacks of heat treatment is that it tends to mask the inclusions that give clues to the origin of the stone.
The treatment is permanent--a heat-treated blue sapphire will not revert to its original color, or colorless state. The practice has become so prevalent that it is now more reasonable to assume that a sapphire has been treated than not. Only the finest, most important stones are being subjected to laboratory examination to determine and certify that a stone has not been heat-treated. This is only practical if the stone is of great value. Small stones used in jewelry or run-of-the-mill stones of modest value do not justify certification. Heat treatment is as old as the hills in which the stones are found. The technique was being discussed in the sixteenth century by the brilliant goldsmith Benvenuto Cellini.
There is another drawback to heat treatment, however. Some sapphires, and some rubies, exhibit a special internal structure that results in asterism--there appears to be a star within the stone. These stars are actually rutiles, needle-like mineral inclusions. But heat treatment absorbs the rutiles, so while the color may be improved, the asterism is lost.
Unlike diamonds, where clarity is of prime importance, in colored gemstones the operative word is color. Cut takes a distant backseat in colored stones because their beauty does not depend on reflected light. Most are cut simply, to take advantage of the shape of the rough. There is no ideal cut, as there is in diamonds. Since many colored gems are unevenly colored in nature, the cutter's job is to take advantage of the color present and create stones with uniform appearance.
Colored gemstones may be faceted or polished to a cabochon. In the past, these stones were also engraved on top in the form of fruits and flowers. In India, such gem cutting began during the Mughal Empire period, 1526 to 1761. The Mughals ruled an area that is now the northern half of India, stretching as far north as the Himalayas, to Burma in the east and Persia in the west. The best known Mughal figure was the seventeenth century ruler Shah Jahan, who built the Taj Mahal. Because of the Mughals' Moslem prohibitions, no representation of human or animal life was permitted in their designs. Instead, they relied on leaves, blossoms and berries to enhance the colored stones they used in their work. These carved gemstones were brought to the West by Jacques Cartier, who traveled to India in 1911. Cartier created a range of contemporary jewelry set with the stones. The most opulent of this group became known as "tutti frutti"--the fruit salad designs that combined carved rubies, sapphires and emeralds in one piece.
Cartier often recut the stones because the Indians preserved as much of the weight of the rough as possible, ignoring significant flaws. The backs, especially, were smoothed out to make the stones more suitable for setting in the fine, precise Cartier designs of the Art Deco period.
Rubies and sapphires are also used in the fascinating technique of invisibly set jewelry. Small stones, perfectly matched in color, are set side by side, row after row, with no metal showing. The stones have no visible means of support because all the setting work is done from behind. Popularized by Van Cleef & Arpels, the technique is exceedingly demanding and is rarely practiced today. One of the few firms working in this style is Aletto Brothers of Boca Raton, Florida. Alfred Aletto, working with his son Albert, the fifth generation of the family in the jewelry business, can make no more than 10 pieces of jewelry per year. Each stone is cut precisely to fit the setting; the secret to invisibly set jewelry is the cutting that cannot be seen--the back of every stone is grooved so that it can be fitted along tiny tracks of platinum wire. Alfred Aletto has raised the already difficult art of invisibly set jewelry to new heights, bringing a special grace and artistry to his pieces.
But even he steers clear of emerald for this particular technique. Having made one piece for a special sale of American jewelry held by Christie's, he says never again. The number ofemeralds broken during the process was just too high. Cutting the back of an emerald almost guarantees that you will run into an inclusion or an internal fracture.
Beyond invisible setting, there are colored stones that are truly invisible, such as the tiny jewels set into your 21-jewel wristwatch. These are likely to be synthetic sapphires, man-made since 1902 for use in bearings, gauges, dies and phonograph needles. Their hardness permits precision in very small sizes, perfect for these hidden uses. Synthetic colored stones are produced to emulate gemstones, made from the same natural materials and subject to techniques that seek to emulate nature. They have found their own market among those who want the color of the real thing but don't have the budget for it. Gem dealer Doug Parker is philosophical about synthetics: "I think there is a need for it; people wear fake furs. There is that desire to have what you can't have." And for those who crave star sapphires, synthetics are produced with stars that are even more regular and distinct than those found in the natural stones. They're too good to be true--and they aren't.
Ettagale Blauer is the author of Contemporary American Jewelry Design (Chapman & Hall, 1991).
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