What Are Laser Drilling & Laser Drill Holes? What Are Their Impact?

While most inclusions are created during the natural formation of diamonds, some are byproducts of the diamond-cutting process, and others are man-made intentionally for specific purposes.🎯

Laser drill holes are a major artificial inclusion. You will not find them in diamonds that fall in the VS clarity grade and above. But if you want to opt for budget-friendly stones, you may possibly stumble on them.

Below, we will explain why and how these inclusions are created as well as how they impact diamond value in detail.

What are laser drill hole inclusions? How are they formed?

In diamonds of lower quality, there could be dark-appearing inclusions, primarily in the form of crystals, hindering the stone's light performance and distracting observers' attention from the brilliance, fire and scintillation.

Laser drilling is one type of diamond treatment that dates back more than 60 years. The treatment is performed by using lasers to vaporize a tiny tunnel (20-25 microns in diameter and usually straight in direction) from the diamond surface to the dark or colored inclusion, meanwhile causing it to evaporate.

In general, treaters would boil the drilled stone in an acid solution to further bleach out the dark inclusion. In many cases, treaters would also apply fracture-filling treatment for the stone.

Spotting laser drill holes

👉🏻In short, laser drill holes are the results of laser drilling. They can exist in diamonds falling in lower clarity categories such as SI, and can be detected with a diamond loupe at 10x magnification. Sometimes, it's safer to examine them with a microscope since some unethical treaters and dealers would disguise them by imitating natural characteristics via creating fractures and etch channels.

For average untrained buyers, you can spot the inclusion by a grading report from the vendor. Laser drill hole inclusions are plotted with a symbol of a red dot circled by a green ring.

Laser drill holes vs. Internal laser drilling

Internal laser drilling (ILD) is a new laser drilling treatment first reported by the GIA in 2000. It applies pulsed lasers to focus on the near-surface inclusion, heating it up. Then the inclusion expands and poses stress to extend the connected fracture to the diamond surface. While this process will not result in a surface-reaching hole associated with traditional laser drilling and direct evaporation of interior characteristics, it opens up access in the form of fractures to allow strong acids to arrive at the dark inclusion for bleaching.

Internal laser drilling is not common as the traditional method since it merely applies to the scenario when the targeted dark inclusion is located close to the stone surface. Otherwise, traditional laser drilling is utilized to vaporize for a tunnel. 

Diamond laboratories' research on internal laser drilling is ongoing. If a diamond receives internal laser drilling, you may not find the info in the diamond plotting; instead, you would see a statement in the Comments section of the report: "Internal laser drilling is not shown."

Laser drill holes and fracture filling

Fracture filling is the most common diamond treatment. It improves the visual appearance by infusing molten glass-like substances with a refractive index close to the diamond's into the fractures.

Fracture filling can only be achieved when an opening is present, which can be either natural or artificial.

Laser drill holes provide an artificial opening for glass-like substances to fill the fracture. However, a laser-drilled diamond is not bound to receive fracture filling; conversely, fracture filling does not necessarily require laser drilling into a diamond beforehand.

How do laser drill holes impact a diamond's beauty and value?

Although an inclusion in themselves, laser drill holes are created with the purpose of removing or lightening the dark or colored crystal inclusion; that is to say, the original, untreated crystals theoretically pose a stronger impact on a diamond's beauty than the laser drill holes.📚

As most of the time people observe a diamond faceup, treaters will try their best to create the laser tunnel in a direction perpendicular to the table facet. In this manner, the laser drill hole inclusions typically appear as a tiny opening when observed from above.

Laser drilling contributes to improving a diamond's visual appearance while lifting the diamond's apparent clarity by one grade or two. However, laser drilling possibly leads to durability issues, especially when the diamond is small compared to the tunnel and there are multiple holes simultaneously. Additionally, oil and dirt can get trapped in the tunnel, turning it dark and making the stone less attractive. A laser-drilled diamond may contain fracture filling, which leads to more issues aside from durability.

Attributing to the impacts brought to diamonds and most customers' inherent favor to untreated stones, laser drilled diamonds are sold with a lower price tag than untreated diamonds of similar qualities. Some could even be 50-60% cheaper.

Will lab-grown diamonds experience laser drilling?

Lab-grown diamonds are manufactured under controlled heat and pressure. They offer a unique feature that separates them from their natural counterparts—they lack the inclusions and blemishes normally present within mined stones, making these gems exceptionally pure. Hence, in most cases, lab-grown diamonds do not need to experience laser drilling.

Sometimes, in HPHT-grown diamonds, the metallic flux used to grow the diamond could remain in the stone, showing metallic luster and sharp reflection when observed from different angles. If the metallic inclusion is too obvious, treaters may consider laser drilling for the diamond. Even more so if the diamond is in a higher carat weight or is a colored stone with exceptional color. GIA's Carlsbad laboratory recently found laser drilling in a 2.02-carat Fancy yellow cushion cut lab-grown diamond.

Are laser-drilled diamonds worth it?

Laser-drilled diamonds are an affordable option for buyers who pursue a bigger stone with a pleasing appearance but are tied to a budget. This is absolutely a great choice if the wearer does not care about its treated property.

But you should bear the risk of dirt accumulation and durability in a laser-drilled diamond and care about the subsequent maintenance if it is also fracture filled.💡

Advice?

The Federal Trade Commission (FTC) requires vendors' disclosure of any laser drilling and other treatment for diamonds. It is always recommended to double-check and confirm the facts with the vendor, particularly when the stone owns good qualities but is at a low price. You can confirm some treatments by yourself with the aid of diamond grading reports. But if the vendor cannot provide a report, the stone has also probably undergone fracture filling, which is impermanent; then the diamond does not deserve a high price.

If you want to pick a laser-drilled diamond for your jewelry, ensure you understand the proper care for the stone. It is also a good practice to confirm with the vendor whether a complementary caring service is supplied.

Depending on the location of the hole, you can hide the opening with certain settings if it is close to the girdle, such as prong and bezel settings. If the budget allows, upgrading the cut grade is able to bring about more sparkle for the stone, helping distract attention to the drill hole and whiten the stone as well.

As mentioned, you can also take lab-grown diamonds into your consideration. They are a great alternative to naturally mined diamonds. They barely have severe clarity issues, and they are affordable.