Surface-reaching fractures containing dirt have long been boiled in acid or bleached to remove unwanted inclusions. About 10 years after the invention of the laser, the first laser-drilled diamonds started trickling into the labs. Crowningshield mentions in a 1970s Gems & Gemology article that he had heard rumors of laser-drilled diamonds for several years.

A laser is used to create a tiny channel reaching from the surface of the gem down into an inclusion. Acids are then used to either bleach or remove the inclusion, thus enhancing the diamonds’ clarity. The drill hole may or may not be filled after the inclusion removal is complete.

Identification isn’t difficult, proper inspection with a microscope will reveal the laser “tunnel”. Note that even melée sized diamonds can be drilled so don’t limit your investigation to the center stone of an item!