I collect and sell rare, natural turquoise and find that leaving
the back of a stone unpolished helps to identify the stone as
natural, untreated material.
And you asked,
How does it do that? Treated material can be left unpolished too...
When a turquoise stone is left unpolished, or uncut, you can see
into the "vugs", or crevices in the stone, (if there are any). If the
stone is untreated these vugs will not be filled in with epoxy, or
with whatever treatment is used. Also if the stone is untreated
whatever "motherstone", or "matrix", is showing, (if any), may be
seen as being a different texture than the turquoise, for instance
motherstone will frequently be softer than the turquoise around it.
This is one way of helping to detect natural from unnatural
turquoise, a lot of it is from experience though. I have looked at
thousands and thousands of pieces of turquoise by now and have a
pretty good idea of what to look for.
Thanks for asking.
By the way, I have a LOT of incredible, natural material for sale,
both High-Grade turquoise and High-Grade coral. I would post pictures
if I knew how, maybe I'll try and figure that out soon. Please feel
free to ask questions or to ask for pictures, my email address is
I have what is referred to as "fossil" turquoise as well. It's not
true fossil stone but actually a "fossil replacement" of fossilized
clams that were replaced by the minerals that make turquoise, thus
making "fossilized turquoise clams". This turquoise is from the
Carico Lake turquoise mine. They are also know as "Pseudomorph clams"
and are EXTREMELY RARE.
If anyone has any advice on where I could sell this material please
let me know, I have too much of it to ever use.