Gemstones Treatments

Science is defined as knowledge and that which can be observed and
repeatedly tested. Questions like “Did God create man” or “Did man
evolve from primordial slime” must be believed on faith. Whether or
not a particular gemstone is “natural” can be supported with enough
evidence to be considered a fact. Laboratories such as GIA or AGL
are not shooting from the hip when they print results like
“Enhancement: None” on their certificates. They do have a
scientific basis for their determinations.

The main factors considered are microscopic inclusions and if
necessary other diagnostic tests such as spectrophotometry, X-ray
fluorescence, microprobe, and Raman analysis. The average jeweler
and gemologist will not have access to these sophisticated analytical
tools and testing the majority of gemstones would not be cost
effective unless the result will have an impact on the price.

Determining whether or not a gemstone has been heat treated or
enhanced in some other manner is much less subjective than naming the
country of origin. I believe a competent gemologist with microscope
and many years of comparative study can confidently separate a heat
treated ruby, sapphire, or emerald from a natural ruby, sapphire, or
emerald in the majority of situations.

I believe it is important to have a firm grasp on these issues not
only for sake of the trade but ultimately for consumer reliability
and confidence.

My website shows pictures of natural Kashmir sapphire inclusions.
They are distinctive from heat treated sapphires and sapphires from
other countries of origin. Link to photos:

Ed Cleveland
Denver, CO

Ed & All, Please read again what you wrote. Your writing is the
basis of the problem with gemstone identification. Yes, GIA uses
scientific analysis which means that they can prove within a specific
set of limits that the object they are analyzing is in fact this
object. Change the set of limits and the resulting analysis changes.
That is science. There is no belief. Belief is faith. Faith can not
be proven other than in the heart. Science can and must be subject to
testing, retesting, and proof without belief to be credible.

This is where the doubt comes in gemological analysis and
identification paper work so often called “certifications”, certs for
short. Terms like scientific analysis, fact, and belief are used
interchangeably when they all mean something different. In the end
the customer has a different assumption of what they are buying and
the whole industry suffers from the image of deception.

Gerry Galarneau

Ed, I agree with you , almost. It is my understanding, that even
GIA, in there newly revised Grad Gemologist course states that in
some cases, one can not determine if a stone has been treated or

Daniel Hamilton

Ed, I agree with you , almost.  It is my understanding, that even
GIA, in there newly revised Grad Gemologist course states that in
some cases, one can not determine if a stone has been treated or

As a GIA student who is reviewing for his Graduate Gemologist final
exam, I feel qualified to field this one, and one other, as well.
GIA teaches us about all gemstone treatments which can be detected
with standard gemological testing equipment. The key word here being
standard. Also, that any gemstone that is suspected of treatment
should be sent to a professional laboratory for analysis. We are
also taught that, unless you know the provenance of the stone, you
must assume that it is treated unless proven otherwise.
Unfortunately, gem manufacturers invent new ways of treating
gemstones faster than the laboratories can find ways of detecting
them. For example, the surface diffused sapphires of the early '90s
were easily detected by examination in immersion under
magnification. Today, though, bulk diffusion treatments of these
stones usually requires expensive (at least $500 per stone) SIMS
(Secondary Ion Mass Spectometry) analysis to detect. SIMS uses
high-energy ions to heat a predetermined spot on the sample surface,
which causes the charged atoms to be ejected from the crystal. The
electrical charge enables the atoms to be carried to the mass
spectrometer for analysis. Indeed, ONE cannot determine if many of
today’s stones are treated in some way. Even as I type this, a
laboratory here in Florida is synthesizing diamonds whose diagnostic
gemological properties are far less distinct than past synthetics
and will fool most gemologists today who don’t have multi-million
dollar equipment at their disposal. Even the mighty GIA Gem Trade
Laboratory admits that, due to the rising number of rapidly evolving
technologies in gemstone treatment and synthesis, many gemstones may
pass their inspection as natural stones before the means of
detecting them are developed. So yes, GIA’s revised G.G. program
states that, in some cases, one cannot determine whether a stone has
been treated.

Next item:

You take on, for example, “Pigeon’s Blood” as a designation for a
type of ruby. To me, it’s a concise description of color, just as
"Champagne" is a color designation for a citrine or diamond. When
someone says to me that something is a “champagne diamond,” I can
immediately picture the color of the stone being referred to.

Here’s another sore subject. I’m looking at a flyer that was
produced by Argyle (the mine which unearths the included brown
diamonds that used to be sold as industrial product). This flyer is
titled Champagne Diamonds C1-C7 Color Scale. Below, there are seven
brown diamonds, each ranging in hue, tone and saturation from light,
pale and de-saturated to deep, dark and vividly saturated, and
numbered C-1 to C-7. On the left of the page, the first two are
labeled “Light Champagne”, the second two are “Medium Champagne”, C5
and C6 are labeled “Dark Champagne” and C7 is called “Fancy Cognac”.
Sorry, but I don’t find “Champagne” as a “concise description of
color”. In fact, it describes at least six DIFFERENT colors.
Yesterday morning, I took a break from studying and turned on the
TV. There, in living color, was a lady hawking jewelry that is set
with “Gourmet Chocolate Diamonds”. I don’t find that a concise
description of color, either. Nor would I find “Semi-sweet”, or
"Toll House" to be. Now, I’m looking at a photo of a pink canary.
Too bad the yellow diamonds (don’t ask me which ones, I only go by
description of hue, tone and saturation) already have that
designation, or Argyle could use that for their very expensive, and
much sought-after pink diamonds. Oops, I just remembered; those
diamonds are so beautiful and rare that they don’t NEED a romantic
name to change them from industrial grade bort into a jewelry item.

I don’t want to demean anybody’s idea of what is acceptable in the
gem trade. Its just that, since I finished the Gem Identification
part of my program, I had to be the bearer of bad news to many of my
friends and family that the incredible gemstone(s) they’ve had for
years, handed down as heirlooms, are, in fact, treated or synthetic.
My mother’s birthstone ring, which she has had for 60 years is, in
fact, synthetic spinel. If this post causes even one person in the
trade to disclose a treatment, or learn a more scientific way of
describing gem colors without romanticizing them simply to make a
sale, it was worth it. Oh yeah, one last thing; yes, I’m a student,
but I’m not new to the gem trade. I’ve been a lapidary and
fabricator since I retired from the military in 1993, and a
rockhound most of my life. The G.G. diploma is just something I’ve
wanted to accomplish for a long time, now. Thanks to Hanuman and all
for this incredible group. I’ve learned things here that no school
can teach!

James Duncan

      Other than the few "matrix opals" from Andamooka, Australia
and Honduran "black" matrix opals that are treated with sulfuric
acid and sugar, opals that are sold as "solid" opals are untreated.

Hi Rick. I have a personal opal which is the first black opal I had
ever seen. It hails from Andamooka, it has a black base color, and
it is most definitely not treated with sugar or by the smoke method,
either. Of course, nearly all “black” opal from Andamooka definitely
IS treated; however, this one is not. I can’t begin to tell you how
many Andamooka mine owners have told me at trade shows that this
piece can’t possibly be naturally black. I understand skepticism
about it, because of the nature of average Andamooka material, but
bear with me and you’ll see where I’m going with this. A sizeable
chunk of Andamooka opal was unearthed some years ago weighing 43
pounds. Yes, I said 43 pounds!!! This chunk of opal was appraised in
1980 by Joseph Tenhagen, G.G., F.G.A. as “gem black opal from
Andamooka Australia, valued at $45 per carat”. The piece that is
still left intact can be seen at the following URL: . The base of
this piece is approximately eight inches across. The pieces I’ve cut
from the main one can be seen at and Sure, it’s
marbled through with areas of brown, in some cases, and also the
typical white precious opal of Andamooka fame, but not one bit of it
has been treated in any way. Every slice from this unbelievable
piece has proved to be shot through with the same base colors, not
just limited to the surface, as typical of smoke and sugar treated
material. I also have a few small slabs left of this material that I
slabbed myself, with no evidence of the very shallow surface
treatment that result from sugar and smoke treatments (and yes, I do
have several examples of treated material as well). The larger chunk
of this material still exists in South Florida. I don’t write this
post to “argue” or to “prove somebody wrong”. Rather, I see over the
years that very few even know of the existence of natural black
Andamooka material…even the miners who work there every day! All I
mean to do is to share new knowledge with those who wish to know.
Thanks for hearing me out.



Too true, everybody is convinced that the only true black is from
Lightning Ridge. There are many other black base colored opals. The
opal I mined here in Arizona in the early 90s had some black potch
mixed in with the blue body color. I am seeing some good looking
dark crystal from Coober Pedy too, although I don’t know how stable
it is, having heard conflicting reports. There is of course the
Virgin Valley black opal that none can deny has gem quality play of
color. It is quite beautiful if kept in water. I have one small
piece that I got at Keith Hodson’s store here in Scottsdale that I
cut and polished over 12 years ago and it is still stable. Most is
not. The opal you are showing is not what I would call “gem
quality” although pictures are not always a good way to judge quality
of opal. I will be honest with you and say that if you have ever
held a true gem quality black opal in your hand and watched the play
of color shift and change as you move it you will never mistake a
Lightning Ridge opal for any other. After long familiarity one can
even tell which field it came from.

The only opal I have ever seen that is comparable is the opal coming
out of a small state in Brazil. I will be getting about 1.5kg of
opal from this area in Brazil in a couple of weeks and will post
pictures of the parcel on my web site. I am still in the creation
part of the web site so will post an address when it is ready to go.

I am told that they are also finding black opal in that area of
Brazil, which is one of the only other areas in the world where opal
is found in a sedimentary formation. The sedimentary opal in Brazil
is very much like the opal in Australia, except I am told it is
harder and so makes a better gemstone.

Even the ‘boulder opal’ is in sedimentary rock. It is found in a
Precambrian metamorphic granite which has opal formations thought to
be of the Jurassic-Cretaceous period and during the time of the
creation of the south Atlantic the sedimentary rock was put under
tremendous pressure and became a metamorphic type of granite called
schist. Without having inspected the surrounding geology myself I
must rely on a paper published (in English) by a geologist from the
University of Sao Palo.

You can and do call it what you like, but it’s not black opal. The
standard is lighting ridge. Look at a rub from there; even with no
flash it has a certain look, an overall very deep charcoal black.
People who disseminate incorrect do a disservice to all.