Laser Drilling
Laser drilling on a microscopic scale, enable us to selectively target, remove or significantly reduce the visibility of crystal or iron oxide-stained fracture inclusions.

Unlike fracture-filling, a laser drill hole is considered by GIA to be an internal inclusion which is marked on their certificates just like other inclusions such as feathers, clouds and crystals. the process of laser-drilling is a permanent process.

In contrast to fracture-filled diamonds, GIA does issue their certificates for diamonds with laser drills.

The development of laser drilling techniques have increased the ability to selectively target, remove and significantly reduce the visibility of black carbon inclusions on a microscopic scale.

Diamonds containing black carbon inclusions have been laser-drilled since the late 1960s, a technique credited to Louis Perlman that did a successful test a year after General Electric had made a similar one with a diamond for industrial use in 1962.

The laser drilling process involves the use of an infrared laser (of surgical grade at a wavelength about 1064 nm) to bore very fine holes (less than 0.2 millimeters or 0.005 inches in diameter) into a diamond to create a route of access to a black carbon crystal inclusion.

Because diamond is transparent to the wavelength of the laser beam, a coating of amorphous carbon or other energy-absorbent substance is applied to the surface of the diamond to initiate the drilling process.

The laser then burns a narrow tube or channel to the inclusion. Once the location of included black carbon crystal has been reached by the drill channel, the diamond is soaked in sulfuric acid to dissolve the black carbon crystal.

After soaking in sulfuric acid the black carbon crystal will dissolve and become transparent (colorless) and sometimes slightly whitish opaque. Under microscopic inspection the fine drill or bore holes can be seen, but are not distracting and do not affect sparkle or brilliance of the diamond.

While the channels are usually straight in direction, from an entry point on the surface, some drilling techniques are drilled from within, using naturally occurring fractures inside the stone to reach the inclusion in a way that mimics organic “feathers”.

The channels are microscopic so that dirt or debris cannot travel down the channel. The surface-reaching holes can only be seen by reflecting light off of the surface of the diamond during microscopic viewing such as a jeweler’s 10x magnifying lens or loupe and are invisible to the naked eye.