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Private Client: Laser drilled & filled diamonds

I recently read a comment on Linkedin from one of my connections which piqued my interest.  It was from a jewellery valuer who had been asked to re-value a pair of diamond stud earrings for insurance purposes.  On closer inspection he discovered the diamonds had been laser drilled and filled to enhance the quality without the knowledge of the owner.

What is laser drilling?

It’s a process using a laser to drill tiny holes (thinner than a strand of hair) in the stone, all the way from its surface to an inclusion inside.  This channel is then used to remove the inclusion by either melting it with heat or dissolving it with acid.  This process is used to improve the clarity of the diamond, quite often by one grade, however it comes with a warning.

By laser drilling holes into a diamond, the structure of the diamond is weakened and if numerous holes have been drilled this not only leaves channels but also an empty space where the inclusion was removed.  This may cause the diamond to crack or chip if knocked if bumped.

To fix the holes created by laser drilling there is a process where the holes are filled after its inclusions have been removed.  This is called fracture filling.

Jewellers fill the tunnels and cavities with a crystal substance, making the results of laser drilling even less visible.  Unlike laser drilling, however, fracture filling does not yield permanent result, and this is why it must be disclosed. Subjecting a fracture-filled diamond to heat or ultrasonic cleaning can destroy the crystal filling and damage the stone.

To avoid being sold a diamond which has been laser drilled or filled, you need to ask the jeweller to explicitly check if the diamond has been enhanced by this process.  Also ask to see the diamond under a microscope, which will allow you to see how many channels have been drilled, as this treatment has a marked detrimental effect on the value.

If you would like to discuss our Private Client service with us in finer detail, you can contact me on 07966 240530.

By Clare CarbyPrivate Client Manager



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