I bought some ametrine from Africa, some from Uruguay, and some
from Brazil. So where is the ametrine coming from. All these
dealers were in Tucson.
It is possible that you could find a stone with light amethyst and
citrine of so-so quality from some other location. (Bolivia does not
have an exclusive with Mother N) However it would be the anomaly,
not a commercial deposit like the superb ametrine found in Bolivia.
All the commercial ametrine you see on the market is from Bolivia
whether the vendors know it or not.
A graduate from GIA claimed to me last year that he was trained
by GIA to detect synthetic and treated ametrine from natural
ametrine.
Synthetic ametrine does exist in beautiful colors and clarities that
when cut could easily confuse experts and non-experts alike. You
must check for natural growth features which requires experience
with both synthetic and natural members of the quartz gem family. It
is not impossible, but it does take knowledge to distinguish them.
Mark Liccinni claimed that natural amethyst cannot be partially
treated to become ametrine.
I agree with ole Mark. I have not always agreed with Mark but I do
on this.
Kurt Nassau in his book claims that >quartz can be partially
treated.
You will need to qualify and reference this statement further before
I can answer.
The mine owner in Bolivia last year at Tucson claimed all his
material was natural, untreated.
The ametrine mine owner? It is true that ametrine is all untreated
- meaning: not irradiated, or heated to obtain its bicolor character
I asked him if they heat treated the material to make it
brighter. He said all quartz is heat treated to brighten the
color.
Not true
All these people are supposed to be trained experts.
Who says?
Four Peaks Arizona amethyst is a very small specialty market. It
has minimal to no impact on the commercial amethyst market.
Yes, Four Peaks is real dark and benefits from heating. It falls
more into the “hobbyist” category, where lots of time can be spent
on idividual stones. The large commercial amethyst mines and
localities of the world like: Maraba, Bahia, Zambia, Madagascar,
Guerrero, Pau D’Arco, Rio Grande do Sul, Uruguay, Bolivia, etc DO NOT
require heating in order to sell. You can heat them if you like and
maybe even improve them slightly, but since they come out of the
ground good enough to market it is not worth it.
Heat treatment is undectable in quartz.
That is because it takes place at relatively low non-crystal
disrupting temps of 200-500 C (Unlike sapphire heat treatment
which needs in excess of 1200 C ) IMO these low temps do not even
warrant the same conotation of the word “treatment” since these
temps are easily reached by natural occurences common in Nature on
the surface of the Earth and without the help of Man - ordinary
fire.
Most dealers I have met have told me that heat treatment of
quartz is an acceptable treatment and you can assume that all the
quartz you see has been heat treated.
NOT TRUE! All quartz has not been treated. This is a blanket
statement made out of ignorance. Most citrine is heated amethyst but
NOT ALL, some is totally natural. 99% of amethyst if natural material
is not treated, but there is a lot of synthetic around. Smoky Quartz
can be natural or irradiated clear quartz. You most know your
source. Bright yellow lemon or “Oroverde” is natural quartz material
but irradiated. There are also a whole bunch of “new” colors coming
form Brazil recently like olive, coffee, smoky-yellow bicolor, that
are natural quartz subjected to irradiation by man to obatin these
colors. You must keep updated at the shows and know the people to
know the answers. The answers are known.
Who is right? I deal with about 30 dealers of rough materials.
Are they dishonest and not telling the truth?
Maybe some are and some aren’t telling the truth.
who is honest and how do you tell who is honest?
Knowledge comes form work and experience. The Tucson Feb Show is
the best place for both in this regard.
I have been buying rough since 1978. Who do you trust?
There are many good dealers in Tucson who sell rough and know and
tell the truth. There are also many ignorant $$$ focused dealers who
will tell you anything to make a sale. There are also many foreign
dealers who do not really know or care, they just ask a price take
it or leave it. Often ignorant rough dealers have great stuff at
great prices and haven’t a clue, while the most trustworthy
knowledgeable rough dealers are also the higher priced dealers. This
is where your knowledge pays off.
You must know the truth for yourself or on new items get educated.
It helps to know mineral specimens too when buying rough. It is not
black magic but science. Like everything in Nature, it all fits so
perfectly together that when a piece of the puzzle is missing it is
obvious. Through knowing the science, the market, the locality,
comparables, history, inclusions, other knowledgable people, etc etc
the truth can be determined. Sometimes a mistake is made but rarely
does it go long before the truth is revealed. The Gem Biz is very
active and a small interconnected group. Word of new treatments get
around quickly. As has been the case with the treated “padparasha”
sapphires from Madagascar. Education and Experience are your best
tools. Often things do not fit neatly in the “box” (category) but
if you understand them that is what is most important.
Steve Green www.briolettes.com