A
tribute to the work of Ted Themelis and diffusion treated gem ID!
And
a review of the importance of the immersion cell to gem ID!
In the ISG office our favorite story
is that it took us all of 15 minutes to figure out that the red
andesine sent to us was artificially diffused, which is essentially
true as I did call Lisa Brooks-Pike within 15 minutes of receiving the
parcel with the specimens, and informed her of the facts. But the real
story goes much deeper and involves the work of Ted Themelis, of GemLab,
Inc. on the identification of beryllium diffused sapphires. Ted’s
work has gone greatly unheralded in the industry but was nonetheless
critical in the andesine issue years before the events unfolded here.
(at left, a Be diffused sapphire showing blue halo)
As he did with andesine 2 years ago,
Ted identified the diffusion treatment of sapphire years before anyone
else in the industry. The problem was getting anyone to listen and act
on the issue. But Ted’s work was indeed right on the money, and more
important to us, his work laid out an investigative structure by which
we believe that all diffused gemstones can be identified. Not for the
specific diffusion processes used, but for the fact of the diffusion
itself, which is the important point for our purposes. (andesine
through the immersion cell shown at right and below)
After reading Ted’s book, Beryllium-Treated Rubies and Sapphires,
we started collecting study specimens of these gemstones, over 600
before we were done. And based on Ted’s book we studied all of the
aspects of the identification of diffused gems and came up with three
basic tenets that we find we can apply to virtually all types of
diffusion treated gemstones. We call them the Themelis Tenets. They
are:
1. The diffusion of gemstones will very rarely
impart color in a uniform manner, or in a totally natural color into
the gemstone,
2. The diffusion of gemstones will always leave an
internal or external footprint of some type if the proper observation
conditions can be created, and
3. The immersion cell is the most important basic
tool in the identification of diffusion treatments due to numbers 1 and
2.
By applying these three tenets to the
andesine, it was a simple process to identify the diffusion treatment.
And the same applied to the diffusion of tourmaline that we recently
identified. The tools used: a 20 year old Meiji Techno GM-2T
microscope and the bottom half of a
Dixie
plastic
cup cut to fit over the darkfield well of the scope. With these two
items, and the knowledge we learned from Ted Themelis, we were able to
identify the diffusion treatments of these gemstones….and others. But
that is another story.
Throughout this edition we have placed
images all taken using our plastic cup immersion cell in our 20 year
old Meiji Techno. It proves that you don’t have to have high dollar
equipment to do important gemology. You just need to study those who
have been successful in the past, learn how they accomplished their
goals, and apply their concepts to new projects that come your way.
(diffused tourmaline in all photos below)
And it should also be noted
that Lisa Brooks-Pike was the driving force behind the exposure of the
andesine debacle. Lisa was relentless in research and obtaining
specimens. Lisa set a new standard for how to research an unknown
gemstone. I guess now we will add the Lisa Tenets to our list of
research tools.
We hope everyone has a great
weekend.
Robert James FGA, GG
President, International School of Gemology
©2008 International
School
of
Gemology
. ALL RIGHTS RESERVED
