An etch channel is a narrow channel in a diamond that opens at the surface. It forms where the diamond dissolved along a line defect (a dislocation) in its crystal.
In more detail
GIA calls etch channels rare in natural diamonds, both type I and type II. Their surface openings are rhombic, and some channels wander like worm-like ribbons. GIA graded a 1.77 ct type IIa diamond with a network of etch channels I1.
On a grading report
Drawn in red and green together on the clarity plot of a full GIA report. A Dossier has no plot but can name it in its list of up to four.
Related terms
- Cavity: A cavity is an angular opening in the surface of a diamond. It forms when part of a feather breaks away, or when a surface-reaching crystal comes out during polishing.
- Inclusion: An inclusion is a clarity characteristic inside a diamond, or one that reaches the surface from inside.
- Natural diamond: A natural diamond is a diamond that formed in the earth, about 160 km deep, under enormous heat and pressure. An eruption carried it to the surface.
- Key to symbols: The key to symbols is the list beside the clarity plot. It names the kinds of clarity characteristic on that plot.