Diamonds are specifically known as the hardest mineral and can hold a polish extremely well and retain their luster.  Its hardness contributes to its suitability as a gemstone.  Because it can only be scratched by other diamonds, it maintains its polish like no other and is well-suited to daily wear that is probably why they are the preferred gem for engagement or wedding rings.

But diamonds can sometimes be flawed by its own mineral in terms of carbon inclusions in the gem when, on its way up to the Earth’s surface, it sometimes encounters carbon at different stages of development and the dominant diamond encloses the carbon within itself. The carbon that is black can be seen under magnification and sometimes even to the naked eye in a cut and polished diamond. 

This flaw is corrected by laser drilling, a process developed in the early 1960s by General Electric. The process is to drill into the diamond using a laser beam with a diameter that is 100 times smaller than a strand of hair. After drilling, the diamond is then boiled in acid under high pressure so that the acid reaches the black carbon through the laser-created entrance and in effect “bleaches” the carbon and turns it to white.

It is generally believed that the black carbon is actually removed, but nothing is ever actually removed from a diamond.  The process simply changes the color of the black carbon giving the perception to the naked eye that it has been removed.

Through laser drilling, the defect in the diamond is permanently corrected. The treatment   does not actually alter the diamond’s carat weight and conversely improves its clarity and sometimes the diamond’s perceived color becomes darker by one grade.  This is due to the absence of the black contrast in the diamond that absorbed the diamond’s natural color.

The Gemological Institute of America offers a full grading report of laser drilled diamonds as they consider the laser drilled diamonds to be permanently treated. However, it is GIA’s policy not to offer grading reports on enhanced diamonds because they do not consider the process as permanent.  

Ironically, jewelers seem to lean more in preference to clarity enhanced diamonds than the laser drilled diamond believing that drilling makes a diamond unpure. On the contrary, the laser treatment allows the diamond to release its true brilliance without the visually disturbing black carbon.