Haven't read much here about red andesine

[vickygigi]

One of my favorite RHR is my custom red andesine (3.28 cts step cut cushion) with (4) .84 tdw in VS, F color diamonds. 14kt white gold. I love this ring and this gemstone. It is such a pretty sparkly red. I am new to posting on PS, but I have done some lurking and I've never read posts about red andesine. Why not? Thanks!

 

[VapidLapid]

Maybe you should put "red andesine" in the search window at the top right corner and see what comes up.

 

[chrono]

Andesine has been badly tainted by the scam that JTV started. They attempted to market the gem as highly coveted, extremely rare and untreated when in reality most have not only been heated but diffused.

http://www.jckonline.com/article/284710-Settlement_in_Andesine_Labradorite_Suit.php
http://www.jewelcutter.com/articles/andesine_scam.htm

 

[vickygigi]

Andesine has been badly tainted by the scam that JTV started. They attempted to market the gem as highly coveted, extremely rare and untreated when in reality most have not only been heated but diffused.

http://www.jckonline.com/article/284710-Settlement_in_Andesine_Labradorite_Suit.php
http://www.jewelcutter.com/articles/andesine_scam.htm

Ouch, no good. That's too bad. I bought my loose stone from a reputable local dealer and she made it clear to me that it was a stone she couldn't replace if something happened to it. I paid a pretty penny for it and I'm fairly certain she said it came from Oregon. It did not come from JTV, so I am hoping it is indeed what she said it was. I've bought many beautiful gems from this dealer and she's always been very upfront about treatments, cut quality, windows, zoning, etc. I think this stone is so pretty! Personally, I prefer it to a garnet.

 

[chrono]

Is it red andesine or labradorite (sunstone)? The two are different but many think the two are the same. Labradorite and andesine feldspars are separate members of the plagioclase series. The difference between members of the series is the percentage they contain of calcium and sodium. Some Oregon sunstone have also been diffused. The only way to check for diffusion is via LA-ICP-MS which only GIA and AGL have for labs in the US.
http://www.gia.edu/research-resources/news-from-research/heating-diffusion-feldspar.pdf

 

[minousbijoux]

Is it red andesine or labradorite (sunstone)? The two are different but many think the two are the same. Labradorite and andesine feldspars are separate members of the plagioclase series. The difference between members of the series is the percentage they contain of calcium and sodium. Some Oregon sunstone have also been diffused.

Chrono: do you mean feldspar? I thought labradorite was a type of feldspar just as sunstone is, but that labradorite is the darker colored stone with adularescece and irridescence?

 

[chrono]

Feldspar is a mineralogical family. Within the feldspar family are plagioclases feldspars which includes: Albite, Oligoclase, Andesine, Labradorite, Bytownite, Anorthite. They are separated by their chemistry from the high value of potassium and the high value of sodium: Albite (NaAlSi3O and Anorthite (CaAl2Si2O:

Albite (Na 100%, Ca 0%) AlSi3O8 90-100% Ab ; 0-10% An
Oligoclase (Na 90%,Ca 10%) Al1-2Si3-2O8 70-90% Ab ; 10-30% An
Andesine (Na 70%, Ca 30%) Al1-2Si3-2O8 50-70% Ab ; 30-50% An
Labradorite (Na 30%, Ca 70%) Al1-2Si3-2O8 30-50% Ab ; 70-50% An
Bytownite (Na 10%, Ca 90%) Al1-2Si3-2O8 10-30% Ab ; 70-90% An
Anorthite (Na 0%, Ca 100%) Al2Si2O8 0-10% Ab ; 90-100% An

The RI for these feldspars are not the same. Generally, the boundary between andesine and labradorite is 1.55 but the best way to separate the two is do a chemical analysis of the Na/CA ratio. Sunstone is the commercial name used for feldspar with the spangling effect (aventurescence).

 

[minousbijoux]

Right, my point was that you were calling it sunstone and labradorite, which are two separate subspecies/types of the Feldspar family. I *think* instead of "labradorite" you meant to say feldspar...that's what I was trying to clarify.

 

[minousbijoux]

To further clarify, unless there is a labradorite that actually looks like andesine? The labradorite that I know is the darker grey with adularscent flashes of blue, and the slight iridescence...perhaps there are other types that more closely resemble that reddish andesine that I'm not aware of (quite possible, btw)?

 

[chrono]

Right, my point was that you were calling it sunstone and labradorite, which are two separate subspecies/types of the Feldspar family. I *think* instead of "labradorite" you meant to say feldspar...that's what I was trying to clarify.

You caught me! I left the word sunstone in brackets because typically sunstone falls into the red labradorite category chemically, only that it has copper inclusions.

To further clarify, unless there is a labradorite that actually looks like andesine?

They do look alike, no question about that.

 

[minousbijoux]

To further clarify, unless there is a labradorite that actually looks like andesine?

They do look alike, no question about that.

You see, this I did not know as I've not seen labradorite of a reddish coloring! Thank you for the "teachable moment."

 

[vickygigi]

To further clarify, unless there is a labradorite that actually looks like andesine?

They do look alike, no question about that.

You see, this I did not know as I've not seen labradorite of a reddish coloring! Thank you for the "teachable moment."

And I am learning from all of you! My documentation says Red Andesine. Now, I'm not sure what it is, but I do truly love it! Thanks for your responses. I feel very welcomed. : )

 

[VapidLapid]

more labradorite with color





Amazonite, too, is a feldspar, and as I saw in the palagems newsletter yesterday can rarely be found in transparent crystals. I had assumed it was polycrystaline like chalcedony since I'd only seen it opaque.
Even Mars has feldspars. Boy I'd like to get some martian moonstone!

 

[LD]

Labradorite is typically grey with labradorescence. Sunstone however can come in a range of different colours (commonly orange) but also grey so grey Sunstone can look very much like Labradorite. For me, Andesine (especially the red variety) is different because it doesn't have a schiller (typically).

Unfortunately most red andesine (even those sold by reputable dealers) have come from one or two sources and it normally treated as Chrono as said. If I remember correctly JTV (and other vendors) were saying that it had either come from Oregan OR from high up in the mountains of Tibet(????) and the location of the mine was highly secret - possibly because the "mine" consisted of a treatment lab

 

[chrono]

Don't laugh but GIA managed to find red andesine in Tibet.
http://www.gia.edu/research-resources/news-from-research/andesine-mines-Tibet-Inner-Mongolia.pdf

 

[LD]

Don't laugh but GIA managed to find red andesine in Tibet.
http://www.gia.edu/research-resources/news-from-research/andesine-mines-Tibet-Inner-Mongolia.pdf

Didn't they use this Tibetan mine as "proof" that the red andesine's were not treated and originated from there? I seem to recall that but it's so long ago now it's very hazy!

Interestingly, just before the scandel, I bought a few colour-shifter andesines from Tibet that looks remarkably like the one in the GIA photo! Now, whether they came from the mine or from the man up the side of the mountain with his lab on the back of his yak is anybody's guess!

 

[chrono]

Didn't they use this Tibetan mine as "proof" that the red andesine's were not treated and originated from there? I seem to recall that but it's so long ago now it's very hazy!

I think they did. Yes, it's been a while and I don't recall all the excuses given.

 

[vickygigi]

Labradorite is typically grey with labradorescence. Sunstone however can come in a range of different colours (commonly orange) but also grey so grey Sunstone can look very much like Labradorite. For me, Andesine (especially the red variety) is different because it doesn't have a schiller (typically).

Unfortunately most red andesine (even those sold by reputable dealers) have come from one or two sources and it normally treated as Chrono as said. If I remember correctly JTV (and other vendors) were saying that it had either come from Oregan OR from high up in the mountains of Tibet(????) and the location of the mine was highly secret - possibly because the "mine" consisted of a treatment lab

Wow, I didn't realize. I think I am going to have to pretend I don't know this info and still love my ring. It truly is lovely. I do appreciate knowing the info though and being welcomed to this group. I have 2 daughters and I am building a custom white gold & platinum ring collection for them to inherit one day (but for me to wear today - ha ha).

 

[LD]

Labradorite is typically grey with labradorescence. Sunstone however can come in a range of different colours (commonly orange) but also grey so grey Sunstone can look very much like Labradorite. For me, Andesine (especially the red variety) is different because it doesn't have a schiller (typically).

Unfortunately most red andesine (even those sold by reputable dealers) have come from one or two sources and it normally treated as Chrono as said. If I remember correctly JTV (and other vendors) were saying that it had either come from Oregan OR from high up in the mountains of Tibet(????) and the location of the mine was highly secret - possibly because the "mine" consisted of a treatment lab

Wow, I didn't realize. I think I am going to have to pretend I don't know this info and still love my ring. It truly is lovely. I do appreciate knowing the info though and being welcomed to this group. I have 2 daughters and I am building a custom white gold & platinum ring collection for them to inherit one day (but for me to wear today - ha ha).

Very sensible! Enjoy wearing your rings!

 

[vickygigi]

Labradorite is typically grey with labradorescence. Sunstone however can come in a range of different colours (commonly orange) but also grey so grey Sunstone can look very much like Labradorite. For me, Andesine (especially the red variety) is different because it doesn't have a schiller (typically).

Unfortunately most red andesine (even those sold by reputable dealers) have come from one or two sources and it normally treated as Chrono as said. If I remember correctly JTV (and other vendors) were saying that it had either come from Oregan OR from high up in the mountains of Tibet(????) and the location of the mine was highly secret - possibly because the "mine" consisted of a treatment lab

Wow, I didn't realize. I think I am going to have to pretend I don't know this info and still love my ring. It truly is lovely. I do appreciate knowing the info though and being welcomed to this group. I have 2 daughters and I am building a custom white gold & platinum ring collection for them to inherit one day (but for me to wear today - ha ha).

Very sensible! Enjoy wearing your rings!

Thanks. I really am happy I found PS and I am looking forward to learning more on this site. I have about 11 colored stone RHRs including the andesine, an unheated 4 ct blue sapphire (that one really set be back), imperial topaz, orange zircon, fancy cut pink topaz, etc. I plan to buy more stones and want to do so in a careful manner. Again, thanks for all of your replies and valuable info.

 

[chrono]

Knowledge is power. Doesn't matter that you now know it is treated - you still love it, right?

 

[vickygigi]

Knowledge is power. Doesn't matter that you now know it is treated - you still love it, right?

Right!

 

[PrecisionGem]

I have never heard of the stones from Oregon being treated. The treatment of the stones from China is kind of a guarded process that isn't known to the Oregon miners. I really doubt any facet gem grade material has come from Tibet. There was an attempt a few years ago to "prove" it did, but no actual mine was found and some low grade reddish brown feldspar stones were dug up. This certainly didn't prove that the thousands of large clean faceted red stones every came from Tibet.

There have been other claims of stones coming from the Congo. This again has never been verified.

If you are buying Oregon stones, than these have not been treated. The colors can range from almost colorless to red or green and even a mix of red and green. Many of the Oregon stones have copper shiller in them. These are often cabbed or carved, and it the shiller is not too prevalent they can be faceted and produce interesting stones. Fine red stones from Oregon are fairly rare, can be expensive, and pretty.

 

[vickygigi]

I have never heard of the stones from Oregon being treated. The treatment of the stones from China is kind of a guarded process that isn't known to the Oregon miners. I really doubt any facet gem grade material has come from Tibet. There was an attempt a few years ago to "prove" it did, but no actual mine was found and some low grade reddish brown feldspar stones were dug up. This certainly didn't prove that the thousands of large clean faceted red stones every came from Tibet.

There have been other claims of stones coming from the Congo. This again has never been verified.

If you are buying Oregon stones, than these have not been treated. The colors can range from almost colorless to red or green and even a mix of red and green. Many of the Oregon stones have copper shiller in them. These are often cabbed or carved, and it the shiller is not too prevalent they can be faceted and produce interesting stones. Fine red stones from Oregon are fairly rare, can be expensive, and pretty.

Ok, now this response makes me feel all happy! I did pay a fair bit for this stone and I was told that I wouldn't be able to replace it as rough is harder to come by and in my size it would have to be cut from rough. This stone truly is stunning, so I am happy to believe that it is indeed natural.

 

[chrono]

Gene,
Here's the million dollar question(s):
1. Is it andesine or labradorite? All she has is the receipt.
2. Is it from Oregon or other locale? Again, she thinks it is from Oregon.

All we are doing is speculating. Knowing the answers to the two questions above can change the value of the stone quite a bit. If it is an Oregon sunstone, all is great! If it is red andesine, is it truly from Oregon or elsewhere? Then this leads to the question of diffusion if it isn't from Oregon. I know some have mistakenly thought a stone is from Oregon when it isn't and vice versa.

 

[vickygigi]

I don't have a receipt. I have an appraisal from my jeweler (a custom jeweler, not a chain). She is a certified gemologist, would she put her reputation at risk to tell me a tale? Especially since I am a repeat buyer? Maybe I am naive, but I trust her.

 

[chrono]

Not all gemmologists are knowledgeable about less well-known coloured stones, focusing primarily on diamonds with the occasional sapphire.

 

[PrecisionGem]

This is a crazy business, I think there needs to be some level of trust someplace. Say you purchased an Oregon Sunstone. How do you know it came from Oregon? Because the dealer told you? I buy the rough from some Oregon miners, and I need to trust that they really mined the stone in Oregon. Did they buy the rough from some treater in China? I really doubt it. I have NEVER seen any rough material that was facet grade that was claimed to be from Tibet, only cut stones.

The rough from Oregon is easy to spot, this is what it looks like. The color is always on the inside, quite different from the treated material.

 

[VapidLapid]

funny thing about that photo, they look like ice in moss, which is funny because Chrono earlier today said of something else that it is moss in ice. ok not funny, just a peculiar happenstance.

 

[chrono]

Gene,
Unless I am buying from a lapidary or see the rough, how else would I know? Trust is good but how do I verify an already cut stone?