Muzo and Cosquez, two of the three most important Colombian emerald mines, are running out of rough. Unless modern exploration techniques are put to work soon, dealers will have to look elsewhere for fine quality emeralds.
This startling news was not the crisis that Colombian and international emerald wholesalers expected to confront at the First World Emerald Congress, held in Bogota this past February. Their thoughts were on the treatment “crisis” – on whether emeralds should be enhanced and whether the use of synthetic resin fillers has caused the fall in emerald prices. But low-key mineralogical presentations turned the spotlight from treatment to supply. It was a rude awakening for the trade.
Rightly so. About 60% of the world’s finest emeralds come from the Muzo, Cosquez and Chivor mines, with Muzo and Chivor yielding the best of the best. But recent recovery at Muzo and Cosquez has been sporadic at best and only two minor deposits have been uncovered at Chivor in the past two years.
Are the mines really running out of emerald? Technically, expert geologists do not think so. But, practically speaking, unless modern methods are used soon, known deposits very likely will be depleted and the Colombian emerald may become a gem of the past.
The unexpected news on rapidly dwindling supplies emerged at a technical seminar by a French mineralogist. The shock waves were such that the speaker, Alain Cheilletz, Maitre de Conferences at the Centre de Recherches Petrographiques et Geochimiques in Paris, was invited to repeat his talk the following day in the main conference hall. “Cosquez may play out soon [in just a few years], so exploration must take place in order to maintain any kind of production,” Cheilletz declared. Unless modern exploration tools are used, new reserves most likely will not be found, he added, and the mine eventually will close.
Cheilletz’s gloomy prediction drew support from William Rohtert, former manager of gemstones for Kennecott Exploration, now an independent economic geologist and project consultant. “Most [Colombian emerald] mines may be losing their resources, depleting their emerald supplies,” he said. But Rohtert is betting his expertise that as-yet-undiscovered emerald deposits lie in the mountain ranges where Muzo, Cosquez and Chivor are located and that high-tech exploration will find them.
When the Colombian mines were first developed, exploration depended mainly on intuition. Within the past 10 years, however, scientific exploration has discovered deposits that once would have been missed. Today’s sophisticated miners use orbital and airborne remote sensing of mineral districts; detailed investigations of the geology, geophysics and geochemistry of mine sites; core drilling that assesses mineable reserves; mechanized bulk mining (i.e. Chivor) and mass extraction of gemstones.
The problem is that mining in Colombia has yet to adopt many of these methods. Lack of funds is a major factor. Political instability and the physical dangers of working in violence-prone areas are others. But if modern methods aren’t adopted soon, the cost to Colombia could be unbearably high as its emerald supplies run out.
Enhancement: why so much fuss? Although the treatment issue was not the sole focus of the conference agenda, it did command a lot of time and talk. Perhaps the most interesting point to emerge from the discussions is that the treatment “crisis” – brought to a head by the Fred Ward case in the U.S. and by falling emerald prices – isn’t considered much of a crisis by the Colombians. To them, and many cutters and wholesalers, emeralds must be enhanced, just as a diamond must be faceted. It is a natural part of the fashioning process.
For Colombian esmeralderos, the key question is, “What kind of enhancement should be used?” In this male-dominated country, they like to compare their product to women. Emeralds, they say, need enhancements to show them in their most beautiful state, just as a woman uses lipstick and blush to enhance her beauty. The language itself supports their belief that “la esmeraldas,” the feminine gender, must wear make-up.
The trade in Colombia sees absolutely nothing wrong with enhancements, as long as they are natural and do not add color. Debates at the congress dealt not with oiling or not oiling but with the relative merits of cedarwood, palm oil, Canada balsam, Opticon, Gematrat or even a combination of epoxy resins. Opticon and palm oil (both synthetic) change color over time, while Gematrat (also synthetic) is a more or less permanent product. Canada balsam is used to seal the cedarwood oil.
Emerald dealers in Colombia are struggling to find the best medium for enhancement. Merck, a U.S. chemical company, produces cedarwood oil but has changed the formula for better use in microscopy over the past ten years. One likely outcome of the congress is that Colombian dealers will ask Merck to reproduce the original cedarwood and develop a better medium. Until this happens, the Colombians must pick something. For now, they seem to agree, at least in spirit, to use only cedarwood oil. This means that buyers of emeralds cut and polished in Colombia can be fairly sure they’ve been enhanced with this oil.
They may not realize, however, that more than 80% of Colombia’s production – including all of the lower quality – is shipped to India for cutting and there are no guarantees on what enhancement is used outside Colombia. It wasn’t too long ago, for example,
that emerald cutters in India were using colored oil. Their attitude was that if oiling improved the appearance of “better” quality stones, then green oil certainly would enhance that of “lower” qualities.
Today the international trade considers use of green oil fraudulent, so traditional treatment labs avoid it – although dealers do come across such treatment on occasion. The word is that some emerald Indian treatments use Jojoba oil.
Imposing past, messy present. Colombian emeralds have a long history. The deposits at Chivor, located high in the eastern highlands of the Andes Mountains, actually date back approximately 64 million years. The first Chivor emeralds were uncovered about 1000 B.C. as the natives, moving from the plains to the mountains, began to explore the region. As native travelers continued west over several smaller mountain regions, they encountered the deposits of Muzo and Cosquez – at 32 million years, much younger than Chivor. In 1564, Muzo would become the first commercially developed mine for the conquering Spaniards.
Muzo is a black calcareous shale deposit where the emerald has intruded up through the soft shale. In its Spanish-controlled years, the mountain was stripped to reveal the green gems and most recently – in the mid- to late 1900s – bulldozed to recover the emeralds in the white calcite intruded veining. Loose shale clogged the rivers far below, attracting thousands of independent miners, the gareimpieros, ever hopeful of finding stones the miners had missed. Today, underground tunneling has replaced strip mining and a journey, in a thankfully modern elevator, to the 130-meter level quickly reveals how basic the mining techniques are.
Common practice in the mine is to follow the vein until you strike a pocket of gems. With most everything black from the shale, and with any visible veining narrowing down and disappearing at every turn, mining and exploration seem primitive. There are few modern tools, only picks, shovels and jack-hammers to loosen the relatively easy-to-crumble shale.
The mine is hot, well above 90°, with little ventilation and 100% humidity from the underground waters which, at this depth, seem to flow directly out of the walls. My camera refuses to operate in the heat and humidity.
Irrigation channels grooved into the tunnel floor drain the excess ground water to the main shaft where it is pumped up and out of the mine. The tunnels are held in place by cement posts and large timbers. One can walk upright for most of the way, but crawling through small openings becomes the norm when moving from one level to another to reach the current mining area. Black shale is everywhere, with no way to avoid it. We wear boots and hard-hats to keep us from slipping and to protect our heads from falling debris.
A full, hard day of mining yields little beyond the black goo that covers almost every exposed area and lightly dusts your lungs and sinuses. When emeralds are found – which doesn’t appear to be too often – the crystals can be of fine quality in size, clarity and color. After only half a day underground, we get a new appreciation of why emeralds cost so much.
The Cosquez mine lies in the same mountain range as Muzo, but is made up of gray shale, a material less permeating than Muzo’s black. Here, too, strip mining (dating back to the 1600s) has given way to tunneling. Starting 500 meters below the mountain peak, the main tunnel travels 1,500 meters straight in, with side shafts following the indicators of albite.
It’s quite a feat to walk into the mine or push a mine cart. The walls and ceilings vary in height and width throughout the entire length of the tunnel, with ground water up to half a foot deep in some sections. The tunnel grade channels the water to the outside.
The ceiling is so low in places we have to walk in a crouch. Walking is slippery and dangerous even with boots and hard-hats. One recently explored side shaft shows signs of complete collapse as the ceiling falls in around us – with no sign of emerald. Muzo’s black shale and Cosquez’s ground waters destroy my shoes and pants.
The output from Cosquez is quite commercial, with numerous oilable “fissures” – a condition referred to locally as “porous.” It may have been caused by the passage of geologic time or by recent jack-hammering.
The Chivor contrast. High in the mountains on the eastern side of the Andes lies Chivor, one of Colombia’s oldest and most important emerald deposits. Here is a picture-perfect example of a modern mining concern, starting with its computerized offices, producing three-dimensional charts of projected tunneling, mining techniques and geological surveys. The mine itself is equipped with the very latest in mining gear, right down to the jump suits, gloves and hard-hat lights.
The entrance is large enough to give access to a full-size truck, allowing quick travel into the mining areas. Lighted tunnels with directional signs make you feel as if you’re inside an underground city. When we reach the point where the truck can go no further, it’s a breeze to go on foot. The floor is relatively smooth and the ceilings a good 10 feet high. There appear to be plenty of pyrite indicator materials in the ceilings and walls. Actively mined areas are set with explosives ready for blasting.
Alberto De La Canpa, former Cuban exile and one-time Wall Street broker, is now mine director. He boasts of a fine operation, but has little production to show even though prospects look very good for major emerald deposits. Reorganization of the mining operation is taking longer than anticipated.
Within the last two years only two smaller deposits have been mined, each yielding less than $500,000 worth of rough emerald crystals (small in relation to investment and anticipated production). But what they do recover is quite spectacular! In Tucson this year, we saw the results – stones of good clarity with exceptional bluish green color, emerald cuts of 10, 15 and 20 carats, priced at $12,000 a carat.
Epilogue. Muzo and Chivor are the two most important sources of emerald in the world. Their production is remarkable for its vivid saturation of color along with size and limited numbers of fissures. Muzo gives us stones with pure green hue, Chivor those with a bluish green.
As we look ahead, Chivor is in a good position. But there’s little hope of finding large deposits or introducing modern exploration any time soon at Muzo and Cosquez, which account for most of the country’s production. Without these two at full production and unless new reserves are found, Colombia faces the prospect that the world soon will turn to Brazil, Africa and Afghanistan to meet its supply needs.