Trapiche Emerald

Trapiche emerald is a rare and highly valuable variety of emerald gemstone that features a unique star-like pattern (like wheel spokes). This beautiful gem variety is highly revered by the serious gem collectors and high-end jewelry designers for making expensive jewelry pieces.

What is a Trapiche

Trapiche is a gemstone distinguished by a distinctive hexagonal pattern of inclusions that radiate outward from the stone's center. This pattern, reminiscent of the spokes on a traditional grinding wheel, is a result of specific geological conditions during the crystal's formation. The term 'trapiche' originates from the Spanish word for such a grinding wheel.

Trapiche Emerald

The most striking feature of a Trapiche emerald is the presence of a six-pointed star or wheel pattern. The "spokes" of the star are formed by dark inclusions, typically made of carbon or other minerals.

Despite its starlike appearance, this unique “spoked” pattern isn’t a case of asterism (the “star stone” effect). However, trapiche emeralds may reveal chatoyancy, a “cat’s eye” effect. Parallel growth tube inclusions can create a cat’s eye in the “pie-shaped” sections as well as, rarely, along the length of whole cabbed trapiche emeralds. Expert lapidaries can orient and cut these stones to bring out this effect.

Trapiche emerald from Muzo Mine, Colombia. Photo Credit: Left Photo by: Luciana Barbosa, Right Photoby: © Martin Slama

When emerald miners first discovered these patterned gems, they called them trapiche, the Spanish word for the multi-spoked cogwheels rotated by oxen tied to a yoke to grind cane sugar. They were first described in 1879 by French mineralogist Emile Bertrand at a meeting of the Société Géologique de France.

Where Are Trapiche Emeralds Found

Trapiche emeralds are found in the black shale host rocks of just a few Colombian mines in the western belt of the Eastern Cordillera Basin. Their appearance consists of a central core, six arms and black shale dendrites – a crystalline, branching tree-like structure that forms between the arms and around the core. They are visible when the crystals are viewed perpendicular to the c-axis and are often cut as cabochons to accentuate the six partitions.
 

Very rare crystal Trapiche Emerald from Muso Mine, Colombia. Photo: Cricksgemstone

How Emeralds Are Formed?

During the formation of an emerald crystal, black carbon impurities may enter the gemstone mix. Because of emerald’s hexagonal crystal structure, these impurities may fill in at the crystal junctions, forming a six-point radial pattern. 

In some trapiche emeralds, inclusions of albite, quartz, carbonaceous materials, or lutite may outline the hexagonal emerald core. From there, they extend in spokes that divide the surrounding emerald material into six trapezoidal sectors.

The extraordinarily rare trapiche emeralds are primarily found in the Muzo, Coscuez and Peñas Blancas mines of Colombia. The trapiche pattern is not an asterism, which is a six-rayed star pattern sometimes seen in cabochon-cut rubies, sapphires and other gemstones.

How Rare Are Trapiche Emeralds

Trapiche emeralds are exceptionally rare, owing to their unique formation process which requires precise geological conditions to create the distinctive spoke-like pattern of inclusions radiating from the center, predominantly found in Colombia's Muzo mine. 

Their scarcity is accentuated by their high demand among collectors and gem enthusiasts, which, combined with their limited geographic availability and the specialized cutting needed to preserve their pattern, significantly reduces their presence in the general market, making them a prized and seldom-seen gemstone.

Symbolism and Use

The unique pattern of Trapiche emeralds is often seen as a symbol of natural beauty and the complex processes of gemstone formation. Due to their rarity and distinctiveness, they are often used in high-end jewelry and are prized by collectors.

See also: How Does a Trapiche Emerald Form?
May Birthstone: Emerald