Internal laser drilling is laser work inside a diamond that creates or widens a surface-reaching feather around a dark inclusion. The feather lets a bleach in to make the inclusion less visible.
In more detail
It leaves a feather, not a straight drill hole, so it can look like a natural break. It is a clarity treatment, so the report must disclose it.
On a grading report
Disclosed in Comments as a treatment.
Related terms
- Laser drilling: Laser drilling is a clarity treatment that bores a tiny channel to an inclusion, usually a dark one. The laser then burns the inclusion away, or a bleaching agent enters through the channel.
- Laser drill hole: A laser drill hole is a tiny, surface-reaching tunnel made by a laser beam, usually toward a dark inclusion.
- Feather: A feather is the general trade term for a break in a gemstone. It often looks white and feathery.
- Treatment: A treatment is any process, other than cutting and polishing, that changes a gem's color or apparent clarity. Anyone who sells a treated gem must disclose the treatment.