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turquoise?

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imakedust
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« on: June 06, 2015, 01:40:46 pm »

:) OK, I'm pretty sure it's turquoise. But that's all I'm sure about. I have had this chunk setting around for about 10 years...I cut a little off here and a little there. I'm now down to about a third of what it once was.

It's not quite as blue as the photo, a little more green, not really green, but not that bright of a blue :)
I'm pretty sure it's been stabilized. Because the sandy matrix does not crumble (like others did when I cut it). I'm kind of stuck at the moment because I want to list these in my store but do not have any experience with turquoise other that cutting a few stones here and there. If anyone out there could give me a little more info on it I would really appreciate it. Here are a couple more photos to go by:



Any thing would be of a help, even if you think it could be fake, I would like to know ;)
Thanks! Sheila
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PhilNM
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« Reply #1 on: June 06, 2015, 02:34:14 pm »

A few Turquoise truths. 95% of all turquoise sold both today and for the last 40 years is stabilized or treated in some way. So, if you won't have the provenance saying it's natural and which mine, etc, You need to catalog it as stabilized.
Also  many mines have appeared and disappeared over the years, and now the Chinese are taking any of their own turquoise that looks even remotely like ours, and marketing it as whatever American mine it looks like, as American Turquoise is more valuable than Chinese. They do have some pretty stuff, and if they were to start being honest and using their own mines names etc in their provenance they'd find the value of Chinese Turquoise would climb to rival American which is slowly disappearing due to mines being closed, exhausted, etc.  There is a lot of turquoise out there from different mines that look identical.
Unfortunately, not knowing the provenance, treatment, etc means you can't sell it for top dollar, you're limiting yourself to the low end of the market. And that's a good enough reason to make sure you get that COA, sales receipt with details etc as provenance when you buy rough stone, so you can provide your own provenance.
Yours is pretty, and looks like it could be Kingman among others, but without provenance, you can't claim it came from any specific mine at all.  10 years ago is not long enough to even claim  it is American, as Chinese material has been coming into this country fort the past 40 to 50 years.  I'd just tell people what you know and what you think it is, and leave it at that. Hope this helped!
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imakedust
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« Reply #2 on: June 06, 2015, 02:59:56 pm »

Thank you PhilNM!
Actually that helps a lot :)

I normally don't buy turquoise rough and did not specifically buy this piece. I had gone to look at some equipment that was for sale by a wife who was selling her husbands stuff...never bought the equipment, but I did end up with all the rough in the shop. This one piece of turquoise was a box and I never even knew I had it till about a month later. I was way too excited about all the cool agates and jaspers I had brought home!

I have no problem being honest as to the stabilizing. My main concern was that I was overlooking anything else that could have been done to it...like dying or what ever they call the squeezed together stuff :)
I don't think it has been dyed, but one of the cabs has this odd light area in the center of it...is that normal?

Thanks a lot for your help! Sheila
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Debbie K
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« Reply #3 on: June 06, 2015, 03:39:52 pm »

The color variation can be perfectly normal, and as you have sliced into it and the color looks fairly consistent the odds are that it is not dyed. If it were dyed, the dye would be concentrated on the outside.

To test if your turquoise is stabilized, slightly moisten your bottom lip and drag the stone across it; if it isn't stabilized it will practically drag your lip off, if it is stabilized, it won't. I have no idea if this holds true for the really high quality Persian material, but it's a standard test for American and Mexican turquoise.

I think it's very pretty; I prefer the golden color matrix to the black. The prettiest turquoise I've ever seen was similar to yours but with smaller matrix, it came from Afghanistan. If I could have afforded it ($325!) I would have bought it. The blue looks good to me, at least it isn't a washed out light blue like most of what I have.

Debbie K

P.S. Turquoise can also come in a greenish shade, I forget which mine had predominately the greenish turquoise; I'm sure an expert will weigh in and tell you!
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imakedust
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« Reply #4 on: June 06, 2015, 04:13:43 pm »

Thank you Debbie,
I tried the lip thing :) but I'm not sure I'm doing it right. Tried it with a couple different stones and the turquoise does have more drag to it, more so than rough wonder stone or jasper. It tastes bad, so I'm going to stay with it being stabilized.

It took some fooling with my camera (hate fooling with the darn thing) but I finally got a photo that's a little more true to the color.


not really green, but not that bright blue either.
This may be one that I cut up and sell in person, rather than ship it off to someone who had grand delusions based on a bad photo :)

Thanks! Sheila
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lopacki
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« Reply #5 on: June 06, 2015, 05:29:26 pm »

Sheila,
As I have been cutting turquoise since 1977 and never would cut treated stone for my own work I cut only natural stone, I can't agree that 95% of the turquoise in the last 40 years had been  stabilized or treated in some way. I will say a large portion has been. Here are a few ways to be able to tell if your stone is  stabilized or treated. First if it smelled sweet when you were cutting and grinding its most likely  stabilized or treated . I think the best test for  stabilized or treated turquoise whether rough or cabbed  is to use a BIC lighter or other flame source, hold the piece of stone very near the side of the flame for ten seconds or so then smell the piece, if it is treated again you get a very sweet smell.

Nearly all treated turquoise even if it has been tumbled will show evidence of treating if you look carefully with a 5 or 10 power eye loupe, you will see the resins down in the lowest parts of the stone it usually looks quite shiny or has pooled or balled up again looking very shiny. To me this looks like it has been treated so if you answer yes to the sweet tests you know it has been.

Many people prefer treated stone I know in Asia where they want robins egg blue nearly all stone of this color is treated so it holds its color, this said the last time I was at the Hong Kong jewelry show (1997) treated robins egg blue finished stone was being sold at 20.00 a carat. Your stone is very nice so don't discount this fact, as turquoise is becoming more rare all of it has risen in price over the past few years.

Hope this is of some help ............ All my best ..... Danny
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Debbie K
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« Reply #6 on: June 06, 2015, 10:06:45 pm »

Sheila:

I agree with Danny absolutely about the smell and taste indicating stabilization.

To clarify, I don't mean that it will have a little drag, untreated turquoise will actually grab your lip and pull it.

I prefer untreated stones of all kinds, but I know a lot of folks who want to work with the treated stuff as it's so much more forgiving to work with. I just prefer to work with a high quality, uncracked, untreated gemstone. And anyhow, since I carve, I'd often be carving below the level of where the stone is stabilized.

Debbie K
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imakedust
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« Reply #7 on: June 07, 2015, 08:19:29 am »

Thank you Danny,
This piece had no odor while I cut it, and I have cut stuff that had a horrid odor! And I cut a lot of lab opal which smells. I tried the flame and it has a smell that is similar to ivory soap. So I guess that would confirm that it has been stabilized :)

Good morning Debbie,
Nope, this one did not grab hold :)

I have actually purchased rough that had to be stabilized myself before cutting, like rainbow calsilica. The stuff I used had to be heated after soaking and left a very obvious bubbled mess around the outside of the stone. I must admit that it worked really good, turning mud into stone. This one must have been processed differently.

While I really don't have anything against a stone like that being treated, I also agree that it should be put upfront when being sold. I would always prefer stones without any treatment, but there is some cool stuff out there, and I love trying new things!

Thank you very much for your insight! Thank you all for the help :)
Have a great evening! Sheila
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« Reply #8 on: June 08, 2015, 11:01:27 pm »

I'm really surprised no one has yet mentioned the Zachery turquoise treatment method, which uses no polymers, waxes, dyes etc. and is essentially undetectable without the use of very sophisticated (and expensive!) testing equipment like microprobes and EDXRF spectroscopy.   It's been used for at least 25 years  to treat many tens of millions of carats of turquoise.

Extensive testing by the Gemological Institute of America has shown the proprietary process greatly improves a stone's ability to take a fine polish and may -- or may not -- improve its color without dyes, depending on several factors.  It also decreases porosity which limits the gem's ability to absorb discoloring skin oils, cosmetic lotions, etc.  Gemologically it has properties almost identical to natural, untreated turquoise except with higher levels of potassium.  (I have no idea whether it would pass or fail Debbie's "lip test" since I've never owned a stone I knew for sure was Zachery-treated).   thinking13

Someone was asking which mines are known for producing natural green turquoise.  In the U.S. at least two are Carico Lake, NV, and King's Manassa in CO.  There are no doubt others.

 


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Debbie K
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« Reply #9 on: June 09, 2015, 07:48:34 am »

Gemfeller:

If the Zachery stabilization process seals the stone enough to keep oil out, it would probably keep water out, too, and would fail the "lip" test. I'm going to research the Zachery process today and see what I can find.

I knew someone would know the locales for the greener turquoise. I think it was the Carico I was thinking of, but couldn't remember.

Thanks for the information!

Debbie K
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gemfeller
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« Reply #10 on: June 09, 2015, 11:40:12 am »

Debbie,

I think most issues of Gems & Gemology are now on-line if you don't have this issue in your library:

G & G, Spring 1999, page 4. "The Identification of Zachery-Treated Turquoise."
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Debbie K
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« Reply #11 on: June 09, 2015, 02:26:49 pm »

Thanks for the information; my local club has a library with all the issues and will be open tomorrow, will look it up there.

Debbie
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« Reply #12 on: June 09, 2015, 02:40:14 pm »

Why wait?  There's a pdf file here: https://www.google.com/?gws_rd=ssl#q=gems+%26+gemology+spring+1999

Just copy and paste in your search engine.
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Amethyst Rose
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« Reply #13 on: June 09, 2015, 03:35:01 pm »

Green turquoise has been found at King's Manassa, Carico Lake, Royston area Mines, Demele, Orvil Jack (Blue Ridge) Stenich, and various Chinese mines.  There are others that produce small amounts of green to greenish blue turquoise.  Some of the green turquoise is actually faustite which is the zinc analog of turquoise.  It typically requires lab testing to determine between the various turquoise group minerals and even some variscite is mis-identified as turquoise.

As to the stone shown, it does resemble Kingman material but as Phil states, without providence, you can't claim any particular mine.  Nice looking material with some nice gold webbing.


Bob Johannes
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lopacki
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« Reply #14 on: June 09, 2015, 03:45:04 pm »

It seems funny that I posted regarding green turquoise this morning and came back and its not here.

All turquoise mines produce green turquoise, some more than others. I have been to more than a few mines even in China and always saw green whether in the dumps or in the production. Nevada has produced the finest greens to ever be seen. I think the top three greens were from the Orville Jack mine the Northern  Lights mine and Carico Lake mine, all three of these mines are in the Crescent Valley area of Nevada. All three of these mines are not in production at this time and I doubt they will ever open again. If you can find high grade of any of these three mines the cost will range from 20 to 40 dollars a gram.

The piece posted above reminds me of Royston also from Nevada.

I will try to post images for the three above mentioned mines soon.

All my best ............. Danny
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