When Lazare Kaplan and General Electric first announced the Pegasus
process, the trade thought it might be years before scientists could detect
whether the stones were treated.
But it took a lot less than that. Two De Beers scientists, writing in the
Spring 2000 issue of Gems and Gemology, say they have come up with a way
to detect a "vast majority" of the diamonds. However, for now, this
method is currently not simple enough to be done by most jewelers, according to
reports.
The GIA has also identified a new laser treatment that does not have the
surface-reaching drill hole traditionally associated with laser drilling.
The GIA notes that, in traditional laser drilling, a hole drilled to a dark
inclusion in the interior of the diamond serves as a channel for the strong acid
used to remove or minimize the dark material.
But this new treatment uses laser-generated heat to expand the cleavages of
the diamond so you can pour acid through them, thereby soaking out the black
piques. Naturally, the piques have to be close to the surface for this to
happen. The laser leaves evidence of one or more internal channels within the
cleavage or adjacent to the inclusion, but there is no surface reaching drill
hole, and the lasering is only on the surface.
In a way, this is better than traditional lasering, since it is does not
leave a drill hole. We even question whether it should be called "laser
drilling," because there is no drill involved.
On the other hand, this treatment is worse in some ways because it leaves an
open imperfection, which could eventually gather dust and other particles, and
hurt its brilliance...