Trapiche Emerald

Trapiche emeralds are a rare variety of emerald named after a six-spoke cogwheel used in sugar cane mills (trapiche de cańa azucar in Spanish).

During the emerald crystal's formation, black carbon impurities enter the emerald, forming a six point pattern as they fill in the gaps between growth sectors of the hexagonal crystal structure.

The earliest mention of trapiche emeralds dates back to 1879, when French mineralogist Emile Bertrand described a trapiche emerald at the meeting of the Société Géologique de France.