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Author Topic: Is it Zandrite?  (Read 6803 times)
Gimmejewels
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« on: May 21, 2009, 12:23:40 PM »

A few weeks ago I had an interesting email conversation with a new gemology student about a 10 X 8 mm oval stone she had received in a J*V parcel a couple years ago and had set into a ring.  This conversation took place over a period of a couple of days and it was really interesting to watch the process she went through to identify the stone.

She started out by sending me these pictures and a brief description of how she got the stone.

 

Quote
The pink and green pics are the same ring in different light sources. It was funny when I first got the parcel I set them up by color in a tray and wondered why I had put a pink in the green section, later looked and it was green in the pink section, then it finally dawned on me that it was a color change stone.

It refracts like glass.  The jeweler said it wasn't synthetic because of something with the bubbles (my husband took it to the jeweler) so I am going from what he said and my recall of about 2 years ago.


Hmmmm...bubbles....

Quote
Yes as I recall he said in glass they are many or uniform or something but I really don't recall much. Anyway he said he did think it was a  natural stone.  I really have always thought it was a synthetic even though they were insistent that it wasn’t. J*V also suggested I send it to their independent gemologist to be analyzed for $50.00 and had seriously thought about doing it but never got around to it.


I pressed her for more information (poor woman.  Remember, she's a new student.) She almost pulled the prongs when I asked her for the SG but she kept the ring intact and still managed to do these tests:

Quote
It is clearly 1.52ish much closer to 2 than 3. I used a known amethyst and peridot as a control just to be sure my refractometer was reasonably accurate and they came out in range as listed on my reference chart.  I am not great with the dichroscope but think I am seeing 3 colors. Chelsea filter seeing a change to yellowish greenish, from purpleish pink. Inert from SW/LW.


Then there was this:

Quote
One other thing. I was thinking since the time I got it and discovered it had such a low RI that it might be Zandrite since that is one of the color change stones they have at J*V. I did call them and asked if it was a possibility that a synthetic stone could possibly get into the parcels and they insisted this was not possible and that the stone was not synthetic or simulated. I even sent the refractometer back thinking it may not work properly and many months later ordered another one and still got the same results.


Talk about due diligence!  She sent the refractometer back because she was told it was impossible that there was a synthetic stone in her parcel, and when she did her most recent testing, she used two known stones to make sure her refractometer was giving an accurate reading.

I haven't examined the stone myself, but it sounds to me like she called it correctly in the beginning.

I know she was hoping it was natural, but I think it made a pretty ring, and a great gemology lesson as well!

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Gimmejewels
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« Reply #1 on: May 21, 2009, 03:16:17 PM »

There doesn't seem to be a lot of information available on what Zandrite actually is.  This is the most comprehensive article I've found so far:  http://www.yourgemologist.com/zandrite.html

http://www.penoir.com/stones/zandrite.htm links back to YG article, and adds this: 
Quote
The color change is caused by the rare earth mineral Neodymium. Neodymium is best know for its extremely strong magnetic properties.


This one also mentions neodymium:  http://www.alexandrite.net/discussion/post/zandrite-FRM-324-00001

They probably got their information here:  http://www.jewelrytelevision.com/about_zandrite
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Jamey S.
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« Reply #2 on: May 21, 2009, 10:01:31 PM »

Looks and sounds like Zandrite to me. Since Zandrite is nothing more then dopped glass, yes, there most likely would be bubbles, rofl. As for that jeweler, they shouldn't be ID'ing gemstones if they can't tell the difference between glass and a natural stone!

This is NOT the first time I have heard of a synthetic or Zandrite being found in the "100% natural" gemstone parcels from JTV!! I know of a few folks who have received synthetics and Zandrite as well.

The original color of Zandrite was pink/green to try and mimic that of Alexandrite. There are other colors and color changes now though.

So, no, it really isn't a true synthetic per say, it is just glass. Wink
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« Reply #3 on: May 21, 2009, 10:29:42 PM »

I too have heard that Zandrite is glass based. As for not getting sythetic stones in a JTV parcel, I will confirm that you can.  I have purchased parcels from them that contained lab created stones including lab created spinel.  I don't know if its a careless QC process but are in there.  To be fair, I have a 1.5 carat heart shaped alexandrite that is the real thing that I also got in a JTV parcel.

I believe the only "created" alexandrite that will test as the real thing is a Czochralski alexandrite from the lab in Russia.  I have two of those in my collection and they do not test as glass.
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« Reply #4 on: May 21, 2009, 10:34:21 PM »

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So, no, it really isn't a true synthetic per say, it is just glass.  Wink

You're right, Zandrite is not a synthetic, but from a customer service standpoint, it doesn't matter whether it is synthetic or simulant, it's a miracle stone because it's impossible for there to be one in that parcel. Roll Eyes
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« Reply #5 on: May 21, 2009, 10:43:48 PM »

I too have heard that Zandrite is glass based. As for not getting sythetic stones in a JTV parcel, I will confirm that you can.  I have purchased parcels from them that contained lab created stones including lab created spinel.  I don't know if its a careless QC process but are in there.  To be fair, I have a 1.5 carat heart shaped alexandrite that is the real thing that I also got in a JTV parcel.

I believe the only "created" alexandrite that will test as the real thing is a Czochralski alexandrite from the lab in Russia.  I have two of those in my collection and they do not test as glass.

Congratulations on that heart shaped alex!   You got really lucky on that one. Smiley

Any true lab created alexandrite will test as alexandrite.  I know the best ones are supposed to come from Russia, but I'm not sure where else they may be produced.

There is also a synthetic color change corundum that can be mistaken for alexandrite that has been on the market for many years.
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« Reply #6 on: May 22, 2009, 04:37:28 AM »

Just to clarify the jeweler (a G.G.) that looked at the stone took a quick look under the microscope and said that he could not determine what it was without further testing but said that it was natural. I did not take it myself so I do not know exactly what he said but did say something about bubbles according to my husband but we do not recall if it was that they were or were not there it has been too long. I obviously had concerns about it being a natural gem and wanted to be satisfied with his quick review but it has continued to haunted me. With the thimble full of knowledge I have at the moment and the suggestions from Gimmejewels as to the few tests I was able to try it does appear to be Zandrite. Zandrite is listed as lab created but not synthetic so the glass RI would make sense. If anyone has any suggestions of other tests or details of what I should be looking for under magnification please post. I am sure we have the answer but I am enjoying the detective work and developing a better understanding of how to identify a lab created is going to be as valuable as identifying natural gems.
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Patty Castronova, RGA
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« Reply #7 on: May 22, 2009, 06:33:34 AM »

Well, glass does have bubbles in it.  I call them pretty bubbles because they are well formed and easy to see with a 10x loupe.  Alexandrite does sometimes have what appear to be bubbles but they are more pin dot and hard to see with the loupe.  Alex sometimes have lines that form I guess they are along the crystals and glass doesn't generally have those.

But I will tell you that the refractive index would do it for me.  At 1.52 you rule out most everything.  No color change corumdum or garnet and the bubbles would clinch it for me.
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Lee Little
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« Reply #8 on: May 22, 2009, 11:10:17 AM »

I don't see where it was tested to be SR or DR. That would be a huge clue. When you look with the refractometer simply give the polarizer, the little cap that is over the eye piece, a spin while you are looking at the green line and see if the line moves even a little. If it does not move and the reading is 1.53 or anywhere close, it is certainly glass. If it moves it is NOT glass. The only color change stone with an RI like that would be Andesine. I have never heard of Andesine like that but I would keep that suggestion in mind while looking at it.
If you do see bubbles and you have an RI of 1.52 or anywhere close it is very likely glass. If you have lost your polarization cap and have no other instruments handy like a polariscope, I would look for flow lines. Curvy lines in the texture. That would conclusively ID it as glass. Have fun, Lee
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« Reply #9 on: May 22, 2009, 02:47:59 PM »

To be fair, I have a 1.5 carat heart shaped alexandrite that is the real thing that I also got in a JTV parcel.
You sure about that? Did you have it tested? If so, who tested it? Lab report? What colors does it change? Can you post a picture?

The reason I ask, is an Alexandrite that large, for starters, would be valued at $10K to $20K+, depending on clarity, color change, saturation, cut, etc.! I very seriously doubt that anyone would have it in a parcel of any kind, sorry, not a natural one that is.

Any lab alexandrite will test completely as the natural real thing. The only way to tell is under a microscope with good magnification.

Also, Alex should have NO bubbles at all.
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« Reply #10 on: May 22, 2009, 04:08:28 PM »

Well, this is fun.  Stay tuned...more test results to come, I think. Wink
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« Reply #11 on: May 22, 2009, 07:16:50 PM »

If the stone had anywhere near the clarity I would expect to see in a lab stone, Jamey, I would have absolutely not even bothered to test it and put it in with the lab stones.  However, the clarity is not good, the color change is good but not great and the cut is poor.  I'd value the stone at about $500.

Oh, and the stone is peacock green to ruddy red on the change.  I'd put it Sri Lanka or Africa.  Certainly not russian or brazilian.  That'd drop the value a bit more I think.  Though I have a Sri Lanka Alex that is the same peacock green to ruddy red that I love and wear everyday but the clarity is much better and the color change much more intense.
« Last Edit: May 22, 2009, 07:19:39 PM by hag916 » Logged
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« Reply #12 on: May 22, 2009, 08:26:48 PM »

Okay I checked it in 4 directions and used the filter....did not budge.  I used a known Peridot as my control to be sure I would recognize the change in RI of a DR stone and it was very easy to see.  So I think we can safely say I have a piece of pretty glass in a way too expensive setting. I am almost sorry this is over I have enjoyed the hunt. Thanks to all who weighed in and especially Gimmejewels for all the time and help.
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Patty Castronova, RGA
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« Reply #13 on: June 01, 2009, 04:26:15 PM »

I confess...Curiosity got the best of me.

I am now the proud owner of a 12mm x 10mm Barion cut zandrite I won at auction for $21.00.  The description said 3.75 ct mm, but it actually weighs 4.50 ct.  It's the first J*V auction I've won, and my first J*V purchase in over a year.

Here it is in daylight and in full spectrum fluorescent:

      

It's a very photogenic little stone, don't you agree?

I thought the cut was interesting (I had never heard of a Barion cut before) and, I have to admit, I do enjoy the color change.
« Last Edit: June 01, 2009, 10:21:15 PM by Gimmejewels » Logged

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« Reply #14 on: June 01, 2009, 08:13:39 PM »

I think color change stones are addictive. Alexandrite is a fav of mine (both of my girls are June babies).  And the color change always fascinates me.  I catch it out of the corner of my eye all the time when I wear my ring and it always amazes me.
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