Excerpt from an earlier post.
Even gem quality turquoise will absorb skin oil over time and
darken…All turquoise is porous until stabilized, regardless of
quality. (Which is far from impossible, and will make it easier to
cut without cracking.)
Lindsay Legler (Who only likes carving and cutting stabilized or
reconstituted stones, because they don’t break or discolor )
Lindsay, it seems like a strange approach to turquoise to want it
only stabilized for the sole purpose that the color remains
constant. If a stone cracks it’s usually because it had a crack in
it or it has been treated too roughly. Only a few stones crack
spontaneously, like opal, that can be unstable. I made the original
post about this material and now that I’ve cut quite a few cabs, I
find that it’s quite attractive and takes an excellent polish.
For those interested, my testing of the material shows a range of
hardness between 4 and 5 mohs. Most is 5. Based on the responses
I’ve gotten off this forum privately and publicly, I’ve concluded
that this is very unusual material and not readily available.
Several very knowledgeable people originally even voiced skepticism
that Peruvian turquoise actually existed. But I double checked the
source with the person who originally imported it and found that it
was absolutely from Peru. Also one look at a photo of the finished
stones has convinced every skeptic that it is turquoise, not a form
of chrysocolla that is frequently called Peruvian turquoise. That
other material is a copper ore and much darker.
It seems from my reading that the color of turquoise is generally
influenced by the relative amounts of copper and iron in the stone.
As to the color of this material, it is in the pastel ranges of blue
and green, and tends more towards the green. It’s quite vibrant in
color and some has a nice matrix, although I’ve cut most pieces
without matrix. The colors of the matrix can range from brown
through a darkish olive green to even a bright red and some of the
turquoise has splashes of red in it. It’s also yielding some larger
stones even up to and potentially through the 40 mm range. I have
not yet attacked the largest pieces of rough. It also cuts some
scenic stones.
As to changing color, I’ve cut a piece to wear myself. Before too
long I will be able to tell if it darkens with wear.
If, however, it does darken by absorbing the oils from my skin, I
will consider it rather a nice interaction between me the wearer,
and the jewelry I choose to wear. I suspect the color will still be
attractive. It seems that there are still a great many people who
like the natural untreated stone, go out of their way to find it and
pay a premium to get it. I’m also pretty certain that some of the
harder turquoises will not take stabilizing.
That’s why it seemed odd to have the comment that turquoise should
be stabilized. If it does impregnate, it then becomes largely
plastic. I may be a minority in this, but I prefer my stones to be
stone and mostly untreated. There is something more elemental about
that.
There is a wide range of what is stone these days with multiple
treatments that go from heating to totally fake. The real problem is
that there is way too much that is intended to deceive. To me the
beauty in the stone is in large part that it is stone. Although I’d
rather have all natural, alterations like heat treating and even
irradiating still leave the finished product a stone. Heat and
radiation are after all alterations that can actually happen in a
natural situation, so it remains stone. That is important to me,
though I acknowledge that it is a personal preference.
What should not be a preference is full disclosure of treatments. I
think there are many reasons for that, but one of the main ones has
to be an extremely important element in jewelry that should not be
overlooked. That is that probably most often, the piece of jewelry
is connected with sentiments. It is so frequently associated with an
occasion or the commemoration of an emotional bond.
How many times have I seen stones that people show me that were sold
at a relatively high price but that are not what they were said to
be at sale. Sold through deception. Yet the person who is wearing it
believes that it is authentic and commemorates something important
in her life. To me somehow a deep emotional bond, bound up with a
deception, bases the whole set of transactions, emotional and
commercial, on inauthenticity.
Most people who buy turquoise do not know that it has been
stabilized, or even worse reconstituted making it mostly plastic.
Even worse still are those who end up with just plain fake. I prefer
my symbols of emotion to at least be firmly planted in the truth. I
actually like them from the earth. Of course plastic is made from
petroleum which began it’s life as a natural product. Sorry to go on
so, I guess in the final analysis as long as there is disclosure
customers can make up their own minds, but I prefer untreated
turquoise.
Anyway, if any one wants to see a photo of this turquoise just email
me off list.
Derek Levin
www.gemmaker.com