|
|
Post by cabby on Jul 17, 2024 9:04:26 GMT -5
While examining turquoise in hopes of figuring out which matches which label I noticed that most of the paler ones I’ve looked at so far have this splotchy veiny crackly appearance… what is the right term for that? Does it mean anything specific in terms of quality or treatments? Shows up best on the slabs, but am seeing it in the polished windows of the rough as well.  Update: I think what I am seeing is called “graininess”, which means low clarity. Can anyone confirm that? This is where I read about it: tskies.com/blogs/news/what-is-the-turquoise-matrix#:~:text=The%20final%20variation%20is%20the,to%20the%20classical%20spiderweb%20designs. |
|
|
|
Post by rockjunquie on Jul 17, 2024 10:28:27 GMT -5
webbing or spiderwebbing Most people really like to see it.
|
|
|
|
Post by cabby on Jul 17, 2024 11:19:24 GMT -5
webbing or spiderwebbing Most people really like to see it. I thought webbing was used for the matrix, not the turquoise! Thank you! Guessing it’s something specific to this turquoise mine, since the majority of rough of similar color and matrix seem to have it. Would webbing still be visible if the stone has been stabilized? Guessing I can rule out color treatments since they would have filled it in. |
|
|
|
Post by rockjunquie on Jul 17, 2024 11:35:46 GMT -5
webbing or spiderwebbing Most people really like to see it. I thought webbing was used for the matrix, not the turquoise! Thank you! Guessing it’s something specific to this turquoise mine, since the majority of rough of similar color and matrix seem to have it. Would webbing still be visible if the stone has been stabilized? Guessing I can rule out color treatments since they would have filled it in. I've seen webbing of matrix, but I have also seen what you are talking about. I think that's what they call "water webbing" but I could be wrong. I think it would still show up with dye. But, my gut says this isn't dyed. It could be stabilized. Hard to tell. Is the matrix soft or hard? The matrix, in it's natural state, would most likely be softer than the turquoise. I'm not a turquoise expert, though. I much prefer variscite- turquoises cousin. |
|
|
|
Post by cabby on Jul 17, 2024 12:01:13 GMT -5
I highly doubt any of these are dyed, but still examining each piece for any hint of stabilizing (some are obvious, others I can’t tell). The slabs don’t have any resins or unexpected anything on the exterior matrix, nor any darkening around cracks or matrix on the faces, so I think those might be part of the “natural Evans turquoise “ that I am trying to identify!
|
|
|
|
Post by rockjunquie on Jul 17, 2024 12:33:44 GMT -5
I highly doubt any of these are dyed, but still examining each piece for any hint of stabilizing (some are obvious, others I can’t tell). The slabs don’t have any resins or unexpected anything on the exterior matrix, nor any darkening around cracks or matrix on the faces, so I think those might be part of the “natural Evans turquoise “ that I am trying to identify! It occurred to me that if you can't determine whether it's stabilized or not - just don't refer to it as "natural". I see a lot of stabilized turquoise on eBay that commands good prices. Some of it kinda has to be stabilized.
Stabilization usually imparts a particular smell when you grind it. Maybe, when and if you cut it, you'll notice a decidedly unnatural smell.
|
|
gemfeller
Cave Dweller 
Member since June 2011
Posts: 4,059 
|
Post by gemfeller on Jul 17, 2024 13:01:21 GMT -5
rockjunquie Hate to disagree with you but the majority of turquoise in commerce has been treated by a method that's undetectable by the layman. It's called the Zachery Process, which is detailed somewhat in the link. There's a comprehensive GIA article about it as well but I didn't take time to search for it. toqos.com/blogs/turquoise-blog/secret-potion-turquoise-jewelry-and-the-zachery-methodI don't think calling treated material "natural" is necessarily incorrect. It's devious, clearly, since the objective may be to deceive or mislead. But the material is natural in the sense it wasn't made in a lab, but merely enhanced or treated in one. It's a way of bypassing the elephant in the room for commercial advantage.
|
|
|
|
Post by cabby on Jul 17, 2024 13:14:44 GMT -5
gemfeller I was aware of the existence of the Zackary process as well as how difficult it is to detect, which is why I am also closely examining the cracks for changes in color that may hint at it. In my case, it’s unlikely that these will be treated with that method since I haven’t seen any evidence of materials purchased after the early 80s. I am pretty sure that with the age of this collection, the “natural Evans turquoise” would mean it’s untreated in any way, since the Zackery method was not widely used at that time. Other stabilization is pretty obvious as I can see globs of some type of resin in nooks and crannies!
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 4,059
|
Post by gemfeller on Jul 17, 2024 13:28:12 GMT -5
gemfeller I was aware of the existence of the Zackary process as well as how difficult it is to detect, which is why I am also closely examining the cracks for changes in color that may hint at it. In my case, it’s unlikely that these will be treated with that method since I haven’t seen any evidence of materials purchased after the early 80s. I am pretty sure that with the age of this collection, the “natural Evans turquoise” would mean it’s untreated in any way, since the Zackery method was not widely used at that time. Other stabilization is pretty obvious as I can see globs of some type of resin in nooks and crannies! That's for you to determine. I was merely providing information that hadn't been discussed previously. |
|
|
|
Post by rockjunquie on Jul 17, 2024 13:39:01 GMT -5
rockjunquie Hate to disagree with you but the majority of turquoise in commerce has been treated by a method that's undetectable by the layman. It's called the Zachery Process, which is detailed somewhat in the link. There's a comprehensive GIA article about it as well but I didn't take time to search for it. toqos.com/blogs/turquoise-blog/secret-potion-turquoise-jewelry-and-the-zachery-methodI don't think calling treated material "natural" is necessarily incorrect. It's devious, clearly, since the objective may be to deceive or mislead. But the material is natural in the sense it wasn't made in a lab, but merely enhanced or treated in one. It's a way of bypassing the elephant in the room for commercial advantage. ALWAYS disagree with me if I'm wrong. I defer to you.  |
|
|
|
Post by vegasjames on Jul 17, 2024 17:33:49 GMT -5
gemfeller I was aware of the existence of the Zackary process as well as how difficult it is to detect, which is why I am also closely examining the cracks for changes in color that may hint at it. In my case, it’s unlikely that these will be treated with that method since I haven’t seen any evidence of materials purchased after the early 80s. I am pretty sure that with the age of this collection, the “natural Evans turquoise” would mean it’s untreated in any way, since the Zackery method was not widely used at that time. Other stabilization is pretty obvious as I can see globs of some type of resin in nooks and crannies! Most stabilized turquoise has been stabilized with resin, which is easily detected by heating the piece with a red hot pin. This will burn the resin crating smoke that smells like plastic.
Really not that hard to figure out what the Zachary process is. I have used a very similar process, which I will not get in to as they do have a proprietary process, but if someone knows a little chemistry and reads up in the test results of the material it is very easy to figure out. Because no resin is used though, and what is used in pretty heat stable, this does make the detection without lab equipment difficult.
|
|
|
|
Post by vegasjames on Jul 17, 2024 17:37:14 GMT -5
The larger stone in this group is a piece I stabilized using my process using a chemical cousin of what I am certain they are using in the Zachary process, which I was already using to stabilize certain stones before I even heard of the Zachary process. As you can see it does not fill voids like resin, but it does increase the hardness of the stone.  |
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 4,059
|
Post by gemfeller on Jul 17, 2024 18:01:33 GMT -5
vegasjames I've been cutting, setting and selling turquoise since the mid-1970s and I've learned quite a bit about its properties, including how to ID epoxy or plastic-impregnated material. I am not a chemist nor do I play one on TV. I only know what I learn from gemology associates and the GIA itself. My comments here were based on this article which is now a bit dated. www.gia.edu/doc/The-Identification-of-Zachery-Treated-Turquoise.pdf
|
|
|
|
Post by cabby on Jul 17, 2024 19:06:23 GMT -5
gemfeller vegasjames seems like both of you guys know turquoise! Can either of you answer tell me what those white spots in the turquoise are? In the pale, more opaque stones it looks like streaks or cracks under the surface. In the more translucent stones the spots are significantly smaller (need magnification) and look like small bits of milky film suspended in a liquid. Yeah, I don’t know the terminology to describe it 😆
|
|
|
|
Post by vegasjames on Jul 17, 2024 19:15:28 GMT -5
vegasjames I've been cutting, setting and selling turquoise since the mid-1970s and I've learned quite a bit about its properties, including how to ID epoxy or plastic-impregnated material. I am not a chemist nor do I play one on TV. I only know what I learn from gemology associates and the GIA itself. My comments here were based on this article which is now a bit dated. www.gia.edu/doc/The-Identification-of-Zachery-Treated-Turquoise.pdf I was not debating you, I was just pointing out that most stabilized turquoise is stabilized with resin.
There are several reasons for this.
One is that much of the turquoise is coming out of China, which uses resin stabilization.
Some people stabilize their own stones, and since the Zachary process is a proprietary process, this leaves this out for home stabilization, again unless the person understands the chemistry.
As the article points out, the Zachary process does not work well for very low quality stone, although this should be easy to get around. Mid to high quality turquoise that this process works best for is rare.
Then, there is the cost. Resin impregnation is cheaper. Therefore, the process is mainly gong to be used on the rarer higher grade turquoises regardless to make the treatment cost worthwhile.
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 4,059
|
Post by gemfeller on Jul 17, 2024 20:01:30 GMT -5
vegasjames I've been cutting, setting and selling turquoise since the mid-1970s and I've learned quite a bit about its properties, including how to ID epoxy or plastic-impregnated material. I am not a chemist nor do I play one on TV. I only know what I learn from gemology associates and the GIA itself. My comments here were based on this article which is now a bit dated. www.gia.edu/doc/The-Identification-of-Zachery-Treated-Turquoise.pdf I was not debating you, I was just pointing out that most stabilized turquoise is stabilized with resin.
There are several reasons for this. One is that much of the turquoise is coming out of China, which uses resin stabilization. Some people stabilize their own stones, and since the Zachary process is a proprietary process, this leaves this out for home stabilization, again unless the person understands the chemistry. As the article points out, the Zachary process does not work well for very low quality stone, although this should be easy to get around. Mid to high quality turquoise that this process works best for is rare. Then, there is the cost. Resin impregnation is cheaper. Therefore, the process is mainly gong to be used on the rarer higher grade turquoises regardless to make the treatment cost worthwhile.
I agree that's likely so. I'm guilty of generalizing but I don't know any source that keeps actual records if it's even possible. I just assume all turquoise is treated some way unless I personally dig it. |
|
|
|
Post by vegasjames on Jul 18, 2024 0:03:06 GMT -5
gemfeller vegasjames seems like both of you guys know turquoise! Can either of you answer tell me what those white spots in the turquoise are? In the pale, more opaque stones it looks like streaks or cracks under the surface. In the more translucent stones the spots are significantly smaller (need magnification) and look like small bits of milky film suspended in a liquid. Yeah, I don’t know the terminology to describe it 😆 Could be a number of minerals such as quartz, calcite, dolomite, etc. that the turquoise can trap during formation.
They have little effect on stability of the stone.
The spots may or may not affect value depending on the market. It is like the webbing, which is more desired here in the U.S., but it considered a flaw in the Middle East, where the pure robin egg blue with no inclusions is preferred.
|
|
|
|
Post by cabby on Jul 18, 2024 6:29:37 GMT -5
vegasjames thank you! I would not have expected that to be more desirable, since it seems to be what is affecting the clarity grading of the stone. Doesn’t change the fact that it’s true now, but the “preferred in America” things often make me wonder if they started off as marketing to help sell material that didn’t fit the old standards. 🤣
|
|
|
|
Post by vegasjames on Jul 18, 2024 7:36:22 GMT -5
vegasjames thank you! I would not have expected that to be more desirable, since it seems to be what is affecting the clarity grading of the stone. Doesn’t change the fact that it’s true now, but the “preferred in America” things often make me wonder if they started off as marketing to help sell material that didn’t fit the old standards. 🤣 Very likely marketing has a lot to do with this. Just like diamonds, which are super plentiful, and not as attractive as many other stones. Great marketing has really pushed the sales of these stones though, including the brown and black stones that used to be considered garbage stones. |
|
|
|
Post by cabby on Jul 18, 2024 7:43:15 GMT -5
Can anyone recommend good reference books for turquoise? Eye strain has been slowing down my attempts to sort, but I’ve noticed that some of the nuggets have distinctly different minerals in the matrix than others (haven’t identified them yet). If I can find a resource for common matrix for different mines, I might be able to narrow down the source. Willing to buy books if you know of one that has that info for older mines!
|
|
