Trapiche is a pattern of six arms of inclusions that radiate from the center of a crystal. You see it in a slice cut across the crystal's main axis.
In more detail
The name is the Spanish word for the cogwheels of a sugar mill. It is best known in Colombian emerald and also occurs in ruby from Mong Hsu, Myanmar. The arms are part of the crystal's growth, not reflected light. So, unlike a star, the pattern does not move when the stone or the light moves.
Related terms
- Emerald: Emerald is the green to bluish green variety of the mineral beryl. Chromium, vanadium or both cause its color.
- Ruby: Ruby is the red variety of the mineral corundum. Chromium causes its red color.
- Asterism: Asterism is a star of light that glides across the dome of a gem. Light reflects from fine needles, often rutile, that lie in two or three directions.
- Inclusion: An inclusion is a clarity characteristic inside a diamond, or one that reaches the surface from inside.