How To Detect Laser Drilled Diamonds ?

What is laser drilling?

Amongst the common treatments carried out on diamonds, Laser drilling is one of them. In laser drilled diamond a beam of high energy light is used to bore a small microscopic hair like tunnel from the surface of the diamond to the inclusion just below the surface of the diamond. Then a strong acid is forced through the tunnel into the inclusion. The acid bleaches the inclusion to lighter colour and make it less apparent to the human eye.

This treatment can turn a lower grade diamonds to a fairly better grade. Usually lower than VS clarity grades diamonds are laser treated because though the inclusion has been bleached , a new inclusion in the form of " laser drilled tunnel" has been created. But as a precaution one has to remember that any diamond can be laser drilled.

Tips for detecting of laser drilled diamonds

The drill hole is a tiny hole and can be missed easily when viewed from the surface of the diamond. So it has to be viewed from several angles and usually from the side of the diamond. The drill hole would look like a  tunnel like inclusion when viewed from the sides. This tunnel is usually very short in lenth (near the surface) and not necessarily long going in depth of the stone.

Another way to spot the drill hole is to reflect light off the stone's surface. This will cause the hole to appear as a small black spot on the reflective surface. Running a small steel pin across the "spot" may enable the viewer to feel the catch of the sharp point in the hole, thus confirming its presence.

Laser drill sometimes appears not as a tunnel but also like many curved channels inside a stone. This is because a new method of laser drilling has been developed recently in which laser pulses are used to stress the inclusions inside a diamond. This additional stress causes some of the inclusion to reach the surface. This surface reaching inclusion is used as a channel to "clean" the inner inclusions by acids. So the resulting appearance would not be a tunnel effect but more like worm like channels in the stone.

Some laser drilled diamonds are filled with foreign substance that still reduces the visibility of the hole.

When first introduced, the use of laser drilling was not adequately disclosed to consumers. Even Federal Trade Commission (FTC) guidelines for the jewelry industry did not require disclosure of the practice! Though it is considered a permanent treatment, the Federal Trade Commission has reversed its previous decision now and made disclosure of this treatment mandatory.