Diagnostics of diamonds treated by laser drilling

The most accurate method for identifying a diamond that contains laser-drilled holes is examining the diamond under magnification. The diagnostics implies the use of a gemological binocular microscope, equipped with a fiber-optic light source and accessories for illuminating the studied sample in accordance with the "dark field" technique.

Laser drilling is often followed by fracture filling: fractures are filled through a laser-drilled hole. In such a case, diagnostics of diamonds treated by fracture filling should be also performed.

Features of diamonds treated by laser drilling

The key feature of a diamond treated by laser drilling is the presence of one or a few narrow channels. As a rule, laser-drilled holes look like needle-like channels with a relatively constant diameter. Usually, these holes are rather straight, and their diameter is very small. However, curved and polyline-like holes can be also found. Such holes are made in order to simultaneously intersect a few inclusions, which are close to one another.
In the region where a narrow channel approaches the diamond surface, the channel may enlarge and become observable as a round cross-section.

Laser drilled hole in a natural polished diamond looking like thin white channel

- Carefully clean the sample under study before starting the diagnostics.
- Examine the sample under a gemological binocular microscope. Attentively search for features of diamonds treated by laser drilling.