Turquoise quality identification

[J S Machine]

My grandmother is something like half Native American and was a jewelry designer back in the 60's and 70's. She made a lot of jewelry with turquoise. I recently acquired a bunch of this stuff and I am trying to study them and learn about them. I started reading and trying to understand all the information about them, but I need help.

The main question I have is whether they are stabilized or not. I don't know enough about the appearances to tell if they are. About half of what I have has been tumbled and polished, but the other half is still rough broken rocks and hard to tell anything about.

I'm not sure who to ask about this and I want to know more about what I have. I do have pictures.

 

[pyramid]

I love turquoise so wish someone would reply here, and would love to see your pieces.

Is stabilised not more shiney on the surface? I know I have read it stops some stones from turning green. I believe though that top quality hard stone which is less porous is more valuable. I wonder if the top quality does not change color. I have read that Lander Blue is most sought after and love the look but never found it for sale, then I stopped looking because I read it was being simulated so could be tricked if not knowing what to look for.

 

[pyramid]

Lone Mountain mine turquoise is a top turquoise too and said to give lander blue a run for its money and read pieces made years ago supposed to have held their color.

 

[jordyonbass]

I don't know much about Turquoise - but from what I have read there is a treatment that can be used involving a plastic. The only way to test for it that I know of is to crush a bead and test it by heating an edge with fire. You can actually smell the plastic if it has been treated. How the treatment affects the stability of the stone, I cannot say.

 

[partgypsy]

I wouldn't be able to answer your question, but if you find more information, please update! I also love turquoise, purchased beads off one site (Stones and Silver). I am afraid probably definitive tests would be destructive, but maybe not?

 

[minousbijoux]

I know I am repeating myself over and over (I resisted the urge to characterize myself as a broken record for fear there would be those who had no clue what that meant, lol), but there is a website that we cannot directly link to here that is geared more towards those in the trade. It is an online Gemology site with Gemology in the title. If you google gemology forums I'm sure it will be the first or second link to come up. Anyway, if you ask there, they will be able to help you out. Also, if you do a search there for turquoise, I'm sure you will find many threads on the subject as I recall reading them on a regular basis over there.

 

[bobsiv]

You can use a lighter to heat a pin until it's red hot, then touch it to the stone. Most of the time if it's been stabilized you can smell a chemically odor and you might see some smoke. Stabilized is OK, it won't affect the value much.

Another thing to worry about is dye, especially for the polished pieces. Pictures might help, but to be sure you'd need to saw or break a piece off the stone to see if the color is the same throughout.