Diamonds - Beyond The 4 C's - Clarity Enhancement

Diamonds Index

Clarity Enhanced Diamond

View from Underside

Good Enhancement
The simple act of cutting or polishing a diamond could be considered to be clarity enhancement, and is obviously highly acceptable. It makes diamonds look much better than when they are first dug out of the ground. Also when a polished diamond contains small imperfections or inclusions near the surface, it is possible to polish away the part of the diamond containing them, and this again is an acceptable aspect of clarity enhancement of diamonds.

Lasering
There is actually another form of clarity enhancement which we believe to be reasonably acceptable, although it did cause some controversy when it was originally introduced, and that is lasering.
Laser drilling was introduced in the 1960's, and was initially relatively expensive. Neodymium - YAG lasers are used with a near infrared wavelength of 1.064 microns. Laser technoology has improved, and costs reduced in recent years.
Let's say you have a large or high quality diamond, but one which has a noticeable black or dark inclusion. This can often be caused by iron oxide (rust!), which can occur as an inclusion in diamonds. It can occupy a cavity within the diamond, sometimes in a very thin layer. Using a powerful laser, it is possible to drill a small neat round hole, as small as 0.015 mms (15 microns) in diameter, usually vertically down from the table, and then to inject acid into the cavity. The acid dissolves (actually reacts with) the iron oxide. The resulting iron salt can then be flushed out of the stone leaving a clear cavity in place of one filled with a dark stain. There is of course the addition inclusion caused by the fine laser hole, and it is not usual for this to be filled.
Because there is no addition of non-diamond material, there is no error or deception caused by this treatment in relation to the weight of the diamond, if anything, because a small amount of diamond has been vaporised in the process the vendor has lost some weight, and the buyer has got a diamond of the same external dimensions, but paid for a slightly lower weight.
In our view, it is desirable that lasering should be disclosed, and we would always disclose it as part of our sales procedure, but is probably not fraudulent to omit disclosure, as it can be seen if the buyer wishes to examine the stone, and there has been no addition of extra material.

Laser Marking and Identification of Diamonds
Some laboratories, and others, offer to laser inscribe the girdle of a diamond with its certificate number. Consumers can also have messages laser etched onto diamonds.

Clarity Grading of Lasered Diamonds
Because of the very small diameter of laser drill holes, it is possible to miss detecting them, and they can be concealed under claws. Most gem laboratories will grade lasered diamonds, and simply not the laser treatment in the comments section of their report.

Disclosure
In 1996, the US Federal Trade Commission ruled that laser drilling of diamonds was not subject to mandatory disclosure. In 1999, the World Diamond Congress declared that the disclosure of laser drilling should be mandatory, and following this, the US FTC reversed its earlier ruling.

Internal Laser Drilling
In 2000, a new method of internal laser drilling of diamonds was developed. This uses a laser to heat an existent inclusion creating pressure and causing cracking to reach the surface. The dark material of the inclusion can then be leached out in a similar manner to external laser drilled diamonds.
The new method is known as the KM method, for kiduah meyuhad which is hebrew for "special drill".

Clarity Enhancement of Diamonds

More About Fracture Filling of Diamonds

Diamond 4C's Tour - Next Stop - Carat Weight

Diamond Glossary - An A to Z of Diamonds