Inclusions & Blemishes

Diamond laser drill hole shown on GIA certificate

Laser drill hole as represented on GIA report

Hello, internet friend. If you’ve been following this diamond inclusions series, well we’ve certainly been through a lot together! We’ve learned about bruises and chips together. We’ve bonded over clouds and crystals. I’ve made a series of horrific jokes which you grudgingly read through in order to get to the information you so desperately need. Today, I'm covering laser drill holes.

What is Laser Drilling?

So, what are ‘laser drill holes’? Well, laser drill holes are the result of a laser, drilling into a diamond. Clue’s in the name really if you think about it.

It all starts with an imperfect diamond that undergoes a treatment called laser drilling, in order to zap unwanted, unsightly inclusions away for good. This treatment is usually done if the diamond is otherwise a beautiful stone, but there is a single pesky black crystal (or similar eye sore) standing between diamond mediocrity and diamond greatness. An infrared laser is used to drill a teeny tunnel into the diamond (thinner than a strand of hair). Once the tunnel reaches the inclusion, it is treated with heat or acid in order to dissolve it. Sounds pretty cool, right? The upside of these treatments is that they are very successful at removing those particular inclusions.

There are downsides however. Not only do they reduce the value of the diamond (because the stone is now more fragile and susceptible to cracks etc.), but it will also now sport a little tunnel where the laser entered the stone, like this:

Round diamond that has jagged white lines throughout due to laser drilling

This diamond has an unbelievable amount of drill holes, but it makes a great example.

Now, these treatments are totally legit and quite common within the diamond industry, BUT, if a diamond has been treated in this way, it must be made clear on the diamond grading report accompanying the stone. Please check the accompanying diamond grading report of your potential stone, to see if there are any comments referring to laser treatments or laser drill holes.

Two more points before I leave you. You should be mindful that laser drilling techniques have evolved so much in recent years that it can be difficult to tell the difference between a man-made laser hole and a naturally occurring ‘etch channel’ (click here for more on those). The price difference between these two can be large however.

Finally, if you do take the plunge and buy a diamond that has a laser drill hole (and there is absolutely nothing wrong with that as long as you know!), make sure you let your jeweler know if you bring it in to be cleaned or repaired, as these treated diamonds are easily damaged.

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