Let’s test your powers of visualization. Imagine you are holding an emerald crystal and looking down its barrel, along what is known as the C-axis. As you gaze into the piece, you notice a black- or gray-banded pattern that resembles a pie cut in six slices, each band extending from a hexagonal core to the edge of the crystal. Have you got that?
OK, now imagine you are looking at the same crystal after it has been cut into a cabochon. Assuming it’s cut properly, and the material is of decent quality, you should see the same pie pattern, each wedge demarcated with lines as thick and sharp as the letters at the top of an eye chart.
These freaks of nature are called trapiche (pronounced trah-peachy) emerald. No one knows why, but to date, these oddball emeralds have been found only in Colombia—at or close by the celebrated Muzo mining district.
Just when trapiche emerald was discovered is a mystery. According to John Sinkankas’ indispensable reference book, “Emeralds and Other Beryls,” the earliest writing on this gem is a short article in an 1879 French mineralogy bulletin. Then nothing more is published about it for another 36 years.
This itsy-bisty is amount of literatureis amazing when you think of the gemological heavyweights like George Kunz and Max Bauer, who were writing voluminously at the turn of the century. Yet, for example, there is no mention of trapiche emerald in Bauer’s 1896 masterpiece, “Precious Stones.”
So the $64,000 question is this: Why did word of this Muzo mutant take so long to spread? Could it have been that cutters didn’t, as a rule, like or understand these unique crystals enough to take advantage of them? In any case, long lapidary silence about these stones led gem authorities as august as Robert Webster to wrongly believe the discovery of this gem was relatively recent (in the 1980s edition of his book, “Gems,” Webster put the date of discovery as 1946).
In reality, it’s interest in, not mining of, this gem that is recent, starting in the postwar years and exploding in the 1970s during that decade’s mania for collector stones. Even today, the market for trapiche remains very active. The trouble is, demand far exceeds supply.
“In late 1990, a Seattle jeweler called me for a top-quality trapiche emerald weighing from 3 to 5 carats,” says Robert Linde, Lindeau Gems Inc., New York. “After trying for six months, I gave up the search. There were stones around but none were fine.”
The supply situation is worse now (mid-1992), reports Ray Zajicek, Equatorian Imports Inc., Dallas. “There hasn’t been any production to speak of for at least four years,” he says.
But just in case production resumes, here’s a primer on trapiche emerald.
Spanish for “Wheel”
Trapiche emerald owes its name to the resemblance of its distinctive six-segment banding to the spokes of a wheel used for grinding sugar cane. In Spanish, this wheel is called a trapiche.
Basically, there are two types of trapiche emerald, explains Zajicek. What he calls “Type A” is small, usually 30 points to 2 carats in size when cut, with green banding that is composed of emerald. The second, which he calls “Type B,” is larger (anywhere from 2 to 50 carats after cutting), with black or gray banding composed usually of carbon. It is the latter kind that jewelers most often see and collectors request.
Although the value of trapiche emerald hinges significantly on the definition, completeness and centering of its pie-slice pattern, other aesthetic factors must be weighed when purchasing this gem.
As our ideal-specimen shot on the opposite page shows, this material often boasts a mild chatoyancy (a sheen of shimmering light reflected from inclisions) which, Zajicek notes, Colombian dealers call estrella (Spanish for star). He continues, “Many Muzo stones without trapiche banding are cut for chatoyancy alone and sold as ‘cat’s-eye emerald.'”
While chatoyancy is not essential to the beauty of trapiche stones, it can contribute to value. What’s more, the kind of dense, fibrous inclusions that cause chatoyancy are not considered objectionable. However, Linder cautions, inclusions such as piques and cracks are definite drawbacks.
When evaluating trapiche emerald, pay close attention to color. The reason Linder spent six fruitless months in search of a fine trapiche wasn’t the most of what he saw lacked banding, but that it lacked color. “All I could find were stones with a faded, milky color,” he recalls. “Fine stones must have a deep, saturate, evenly distributed green.”
Lastly, consider the quality of cutting. Whether fashioned into a square or round cabochon, the stone should be symmetrical and its shape pleasing to the eye.
Although rarely used for jewelry in America, trapiche emerald has a small following, almost exclusively male, in Colombia (mainly among emerald dealers) and Japan that views it as an ideal ring stone. In general, men—Japanese men, especially—gravitate toward phenomenon and, to a lesser extent, pattern gems. While phenomenon stones like cat’s-eye chrysoberyl, alexandrite, black opal, star sapphire and even tiger’s-eye are far more popular than pattern stones, they’re not more plentiful. Not when you consider the vast array of inclusion- and picture-agates available.
But trapiche emerald is the only pattern-stone available to consumers that qualifies as a traditional precious stone. Much of its appeal lies in this fact. Nevertheless, even without emerald affiliation, this gem would have much going for it. Couple its broad black bands with its forest green and you have a stone with much to recommend it in the way of macho magnificence. In fact, it may be the ideal pattern-gem for jewelry. Certainly, its use in 3- to 5-carat sizes for men’s rings may account, in part, for the scarcity of fine goods in the U.S.
Given the current dearth of fine trapiche emerald, its cost to jewelers seems a bit of a bargain. No dealer quoted us a price above $1,000 per carat—and that’s only for ideal stones. Did you hear? Superb Muzo emeralds for less than $1,000 per carat! And if you don’t mind stones with incomplete or off-centered wedge-patterns or lighter colors, they can be purchased for under $500 per carat. Stones afflicted with both won’t cost more than $200 per carat. Glaring inclusions will chase the prices of stones with poor patterns and color to under $100 per carat. By this time, however, most jewelers will have lost interest in the stone.
So our final piece of advice: Think fine when you think of trapiche emerald. Then if you’ve got the patience (money shouldn’t be a problem), you might add your name to the waiting list for the occasional fine trapiche that comes on the market.
Please note: this profile was originally published in 1992 in Modern Jeweler’s ‘Gem Profiles/2: The Second 60’, written by David Federman with photographs by Tino Hammid.
The 21-carat trapiche emerald shown in the header image is courtesy of Gonzalo Jara, Santa Fe de Bogota, Colombia.