One treatment to enhance the clarity appearance of a diamond is laser drilling, which consists of using a laser to bore a hole in a diamond. The hole, resembling a wormhole, is used to reach a dark crystal so that acid can be injected to bleach the inclusion and make it a lighter color.
Laser drill holes are usually easiest to see from the side of the diamond. The “wormhole” extends from the surface in a straight line down to the target inclusion. The hole on the surface can often be felt if explored with a sharp pick or needle.
Sometimes the laser drill hole is then fracture filled with a liquid glass-like material to make the hole less visible. Fracture filling is also used in diamonds without laser drilling when it is injected into fractures that reach the surface (feathers). Companies that perform fracture-filling market themselves as being better than their competitors are, based on the proprietary formulas they use for the filler substance. Most fillers react to heat, light, and other conditions, thus changing color or becoming more visible over time.
It is critical that laser drilling be disclosed to the consumer, even though the Federal Trade Commission Guides for the Jewelry Industry do not require disclosure. Therefore, it is up to the diamond suppliers (wholesalers and retailers) to ensure that this treatment is properly communicated, especially to the consumer.
While the purpose of laser drilling is to improve the appearance of the diamond, there is still much debate over how to price these diamonds. Obviously, the biggest danger to the public is if they purchase a diamond that has been laser drilled without being informed of the treatment. Most consumers do not inspect their diamonds under a microscope and are relying on the word of the retailer or on the report from a grading laboratory. The best protection to avoid laser-drilled diamonds is to purchase GIA graded diamonds because the GIA always indicates on the Diamond Grading Report if a diamond has been laser drilled. Laser drilled diamonds should be properly disclosed and sold at a lower price. Since most knowledgeable diamond shoppers avoid laser-drilled diamonds, they become very difficult to resell.
The laser drilling is not to be confused with laser inscription, which is the etching of the certification number on the diamond for identification purposes. The laser-drilling process actually bores a hole into the diamond, while laser inscribing only darkens a thin layer of carbon molecules on the surface of the diamond and does not damage the diamond.