June 2004


Ametrine's New Face

The purple and yellow gem should be seen as a sublime mix of colors, says its producer

Bolivias ametrine production might have ceased by now if not for recent dramatic changes by Ramiro Rivero, owner of Minerales y Metales del Oriente, which operates Anahí, the ametrine mining concession in southeastern Bolivia. Rivero is transforming the mine, the company and the gemstone Bolivians proudly call bolivianita. On a recent visit to Anahí, Professional Jeweler learned about his strategy for change.

Redefining Ametrine

Rivero wants to change the way the market looks at his product, which is found only in Bolivia. Rivero wants jewelers and consumers alike to consider ametrine as a gemstone of variegated colors beyond just the classic 50/50 split half amethyst and half citrine.

That classic split is an inefficient use of rough and not creative enough to reveal the gemstones true inner beauty, he says. Ametrine was always cut to look like bicolor tourmaline. Thats the best way to cut tourmaline because of its elongated crystal structure, but its not the most efficient way to cut ametrine. Cutters must discard a lot of rough to achieve 50/50 because they have to eliminate areas of split color zoning. In addition, 50/50 splits give a jeweler only one option a squarish, emerald-style cut, he says. I want 90/10 or 30/70 cuts or ones where the mix brings up fantastic new colors.

Rivero credits U.S. gem cutter Michael Dyber for this ametrine revelation. He was one of the first to cut ametrine in a way that mixes up colors, he says. Rivero points to several new gem cuts at Minerales y Metales, where reddish, peach, orange and lavender hues are revealed and where shapes other than emerald cuts abound.

While Dybers cutting is innovative and unique, Rivero hopes to persuade artistic cutters to develop repeatable cutting styles. Hes offering royalty agreements to several American cutters for shared plans that enter the market as product lines. He hopes to brand the cuts with the cutters name.

Rivero says a certain percentage of classic cuts will always have a place in the market. His goal is to simply enlarge ametrines appeal. (Prices for ametrine have gone up steadily in the past decade. See Gemstones/Data & Statistics.)

Production at Anahí

In stifling heat, a gaggle of tropical butterflies flits crazily above the gem-washing plant, waiting for a chance to sip the water. Below them, a miner directs his pressurized hose toward a newly decanted dump of rocks. As the water reaches them, rich purple, yellow and lavender crystals turn up: amethysts, citrines and ametrines. These gems are the mainstay of Anahí. Over a dozen mine hands pluck the gems from the sieves and carefully place them in bags for future sorting and classification.

These miners are tackling one of many projects aimed at increasing the production of ametrine and other quartzes, all while holding down costs. They find a surprising quantity and quality of salable gem rough among mine dumps discarded years ago.

Inside the mine, geologists map tunnels using high-tech computer software with the aim of understanding where quartz deposits were missed when old mining methods were practiced. Several new deposits have been found, and samples from various deposits are being classified and documented. This will help us understand our deposit and allow us to become a just-in-time supplier, says chief geologist Alfredo Jacobs.

Mine shafts, once spread higgledy-piggledy across the mountainside, are being remodeled to empty out at a single level, rather than several, to ease the work of heavy machinery used to move overburden. We want to transform this into a world-class mine thats safe and efficient and conforms to ISO 14000 standards, says Jacobs.

Presorting at the mine site is a money-saver too, says Enrique Sanjinez, who manages classification and sorting. In the old days we had a 50% error rate in sorting, causing greater company costs down the line. Now we use sorting specialists and are down to a 5% error rate.

Orchestrating much of the operation, from the mine to the headquarters, is comptroller Jorge Lopez. Computerization tells him what each deposit produces and how its doing against projections. We realized that to make more money, we did not have to sell more we had to lower our operating costs, he says.

Preserving the Pantanál

Rivero is also mindful of social and environmental responsibilities. Anahí is located on the Bolivian side of a nature preserve that borders Brazil called the Pantanál, which means swampy area in Spanish. It swarms with a multitude of caimans, snakes, insects and parrots. Jaguars have been seen loping through the jungle near Anahí, and coral snakes have been known to slither into the mines dining hall. But Rivero has strict rules against hunting and fishing.

The company also hired the Ayoreo tribal community from the nearby village of Rincón del Tigre (Tigers Corner) to patrol the jungles in search of illegal poachers. Rivero is developing plans for future ecotourism as a way to diversify his business.

The efforts of Minerales y Metales del Oriente have been recognized by U.S. entities such as the U.S. Agency for International Development, which rewards and recognizes forward-thinking companies in Bolivia.

The biggest change of all, however, is the way ametrines producers want you to think of the gems many-hued colors. Stay tuned.

by Robert Weldon, G.G.


Ametrine can be cut to show peach, orange and lavender an optical mix of its purple and yellow color zoning. This gem was faceted by cutter Rick Stinson, Wichita, KS.
Classic ametrine, such as this one photographed on top of an ametrine crystal, exhibits 50/50 color zoning. The cutting style, while popular, is not the most efficient use of the rough.
Alfredo Jacobs, chief geologist at Anahí, sits inside a gigantic amethyst geode at Bolivias Anahí mine.
Rough expert Enrique Sanjinez examines an ametrine for quality classification at the Anahí mine.
This suite of fantasy cuts shows ametrine can be cut in repeatable shapes. Each stone maintains an individual character because of its unique color zoning. Gems courtesy of Stuller, Lafayette, LA.

Copyright © 2004 by Bond Communications