Jeffery Bergman is known in the trade as a collector of trapiche gems. These gems, characterized by their six-rayed patterns, are elusive and seldom found in high quality. Mr. Bergman believes people are attracted to the symmetrical pattern, which reflects a natural order in the chaotic world we live in. According to Bergman, trapiche gems are too rare to support a business, so he has also traded many other gemstones during his 50-year career.
As with most gemologists, the first trapiche gems he saw were Colombian emeralds. But it wasn’t until 10 years after this initial encounter at the Tucson gem show that he purchased his first trapiche gemstone: a thick Colombian emerald weighing about 20 ct. Mr. Bergman sliced it in two, increasing the value after it became a matched pair of acceptable thickness.
He saw his first non-emerald trapiche gems at the Mae Sot gem market on the Thai-Burmese border in the early 2000s. Mr. Bergman was handed three Burmese trapiche sapphires from Mogok, something he never knew existed. Other collectors were equally surprised and paid high amounts for these stones, encouraging Mr. Bergman to expand his collection. During those days, many fine Burmese trapiche rubies came out of Mong Hsu while Mogok provided the trapiche sapphires.
Trapiche rough is extremely difficult to judge since the patterns often do not extend throughout the entire stone. In most cases, the most desirable pattern can only be found in the middle of the crystal length.
Trapiche and non-trapiche emerald evaluation are very similar, as the most important characteristics are always the color and transparency of the emerald itself (figure 1). The symmetry and shape of the pattern are only of secondary importance, followed by size and potential treatments.
Trapiche emeralds from Colombia are well known, with the Muzo mine producing the majority. The patterns can exhibit many variations, from perfect six-ray symmetry with high clarity to cloudy stones with broken or incomplete rays. Trapiche-like emeralds have recently been found in Swat, Pakistan, but they show a very different appearance and formation (Fall 2019 GNI, pp. 441–442). Beryls such as aquamarine and bixbite (red beryl) are known to exhibit trapiche or trapiche-like characteristics but they are even rarer than emeralds.
Trapiche corundum gems are mostly known from Myanmar. Trapiche ruby from Mong Hsu is often small. In his 20 years of trapiche experience, Mr. Bergman has only encountered two gem trapiche rubies from Mong Hsu that were over 1 carat. The material is fairly dark, which means it must be sliced thin to appreciate any color, thus reducing the weight of the stone drastically. Heat treatment rarely improves the appearance; it alters the trapiche pattern, making it chalkier and less pronounced.
The Tajik ruby mines have also produced trapiche rubies, as well as the mines in Nepal. Batakundi (Pakistan) and Orissa (India) are other sources of ruby with six-rayed patterns (Spring 2019 G&G Micro-World, p. 114).
Trapiche sapphires from Mogok (figure 2) are often dominated by gray tones or very saturated blues bordering black colors. Only the finest stones show a snow-white bodycolor with vivid blue arms. To date, these are the only true trapiche sapphires. Trapiche-like sapphires are much more common from basalt-related sources such as southern Vietnam, Australia, and even lesser-known areas such as Scotland.
Quartzes, including amethyst and smoky quartz, can exhibit trapiche patterns. A pocket of Zambian tourmalines and some extremely rare garnets also show a six-rayed pattern.
In Mr. Bergman’s opinion, trapiche only applies when the symmetry is sixfold. This excludes more common materials with similar growth patterns like chiastolite. Asteriated diamonds, most often found in Zimbabwe, resemble trapiche when viewed in certain angles, but in reality they contain clouds extending in three dimensions at 90º angles.
In the last decades, knowledge and appreciation of these unique stones has spread and they are now actively sought after by collectors, bespoke designers, and gem enthusiasts. This increased demand and availability has driven gemologists to take a deeper look at these gems and their formation, but there remains much to be discovered.