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 Post subject: Help with suspected CZs
PostPosted: Mon May 17, 2021 11:53 am 
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Hi everyone,

I'm relatively comfortable identifying stones when they are unmounted but I'm still learning and trying to figure out tests that I can do with mounted stones so any suggestions would be appreciated. The one I'm looking at has 144 stones (1.00mm in size) in it and it's 10KT Yellow gold. I was told they were diamonds but there are a couple of things that don't match from what I've seen in diamonds.

Here's what I have so far:
LWUV, basically no reaction
SWUV a lot of the stones on this ring go to a faint-medium green colour

On some of the stones it looks like they might have slightly rounded facets (like that found usually in paste / jewellery glass) but there are some that don't have this. I was told by the jeweller that worked on it last that they put some diamonds into it so I'm guessing it's probably a mix of something with some diamonds but that's what I'm trying to confirm.

I can't get a clear polariscope because it's essentially closed back (just a pin hole for each stone), I haven't tried a spectroscope yet to see if there's a 415 line for diamonds or if something else might show up. Being clear though I wasn't expecting there would be much, if any, reaction there. Looking through the microscope I see some of these stones have some damage to them which, again, isn't consistent to what I'd normally expect from diamonds. There are a few with some hackly fractures on / near the table (one such example is pictured below) and there are others that have a conchoidal fractures.

Based on what I'm seeing my thought is that it's either paste or Cubic Zirconia. Anyone have any other tests / insights that I might be forgetting on how I can identify these stones? Before it's said, I don't have a Raman and there isn't one available nearby unfortunately. I do have pretty much everything else for gemmological tools though and I'm trying to figure out if there's anything else I can do to test these stones.

Attachment:
File comment: Taken through microscope at around 40X power.
IMG_20210516_184458.jpg
IMG_20210516_184458.jpg [ 719.4 KiB | Viewed 1118 times ]


Thanks in advance for any thoughts. I'll take some more pictures soon. I just saw the one I had was a little blurry so I'll pull out my camera attachment for the microscope. (That was just taken with a camera through the eyepiece so it's not very good quality)

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 Post subject: Re: Help with suspected CZs
PostPosted: Mon May 17, 2021 2:18 pm 
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MAGI Labs EXA would separate diamond from CZ, and lab grown diamonds.


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 Post subject: Re: Help with suspected CZs
PostPosted: Mon May 17, 2021 4:48 pm 
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Honestly you should be able to get indications with a microscope.

In a ring of that quality it is unlikely to be set with all flawless stone. If they are all clean, a good indicator that they are not diamond. If they do have inclusions you should be able to see if they are typical diamond inclusions.

Then there are indications from things like finish an polish.

In the end however you should have the tools to do a definitive ID or send the item to someone who does.


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 Post subject: Re: Help with suspected CZs
PostPosted: Mon May 17, 2021 8:31 pm 
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Just an experienced observation I only see two stones that appear to have surface abrasions. would that rule out being diamonds? Ring appears very dirty and in need of a good safe bath. I do not see paste or CZ, based on your image. You have not claimed any of these have tested positive as diamonds, even a relatively priced diamond checker (magic tester) would give you a reading on some of them. I also notice that the the top center, immediately to the right and below, these three stone are not of the same cutting quality of the others you can clearly see in the image. The star facets in these three stones are very poorly cut into the table, with that and the abrasion would lead me to suspect they are not diamonds. But just a big wild ASSUMPTION! I want all of those MAGI tools! :)

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 Post subject: Re: Help with suspected CZs
PostPosted: Mon May 17, 2021 10:30 pm 
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Barbra Voltaire, FGG wrote:
MAGI Labs EXA would separate diamond from CZ, and lab grown diamonds.


I would love to but don't have the money for it yet. Eventually maybe.

1bwana1 wrote:
Honestly you should be able to get indications with a microscope.

In a ring of that quality it is unlikely to be set with all flawless stone. If they are all clean, a good indicator that they are not diamond. If they do have inclusions you should be able to see if they are typical diamond inclusions.

Then there are indications from things like finish an polish.

In the end however you should have the tools to do a definitive ID or send the item to someone who does.


I was taking a closer look through them again and there were a couple that had some nice sharp facets that I've normally seen in diamonds with diamond inclusions but then some of them have more of the rounded facets with basically no inclusions. Being as small as they are it's possible they could still be poorly cut diamonds maybe but some have conchoidal fractures which, to my memory, don't happen usually in diamonds.

glhays wrote:
Just an experienced observation I only see two stones that appear to have surface abrasions. would that rule out being diamonds? Ring appears very dirty and in need of a good safe bath. I do not see paste or CZ, based on your image. You have not claimed any of these have tested positive as diamonds, even a relatively priced diamond checker (magic tester) would give you a reading on some of them. I also notice that the the top center, immediately to the right and below, these three stone are not of the same cutting quality of the others you can clearly see in the image. The star facets in these three stones are very poorly cut into the table, with that and the abrasion would lead me to suspect they are not diamonds. But just a big wild ASSUMPTION! I want all of those MAGI tools! :)


The ones pictured do have some surface abrasions / hackly fractures that I haven't seen in diamonds before in that way. I've seen wear similar to it when two diamond rings are beside each other and rubbing against each other, essentially bruting the diamonds against each other but that's usually on the girdle, not table. I had thought of a diamond tester but with my experience in the past with them they have been pretty lousy when it comes to identifying even with a 50% accuracy. The ring was actually just recently cleaned, the "dirt" that you might see in between the diamonds is actually just unpolished metal from when it was cast.

I had tried taking some better pictures but apparently the camera attachment I have for my microscope is meant more for internal images (work with darkfield) and not that great for pictures where I can't get a good darkfield light through it. I did take the following with the same method as before (camera through eye piece) so hopefully it is enough to help confirm.

I did try spectroscope but couldn't get a clear reading with how small they were. I did however try some visual optics on it and it looks like they do have a higher dispersion and the primaries are pretty close to the light barrier which, assuming stones aren't super shallow or deep, indicates the RI would be in the 2.0 - 2.2 range. Both of these reading suggest CZ as well but with how many stones there are I can't confirm all the stones in this manner, but some for sure are CZs.

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Based on the conversation I've had with the owner and the jeweller that worked on it my best answer at this point is it was bought thinking the stones were diamonds and when the jeweller did some work on it he was told to just replace missing stones with diamonds so there might be a couple real ones in with the majority that are actually CZs. Any other thoughts or insights are appreciated of course. As I said, I'm still getting used to the limitations of having stones mounted rather than unmounted.

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 Post subject: Re: Help with suspected CZs
PostPosted: Tue May 18, 2021 2:59 am 
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I would go with the obvious. 144 diamonds with no LWUV reaction means no natural diamonds.
Only an uniform greenish color in SWUV should rule out HPHT. Why do you think it is CZ?

if these are synthetics or CZ the ring should sparkle like hell in light. You don't mention this and it is also not visible in your pictures (there is no fire at all).

Most logical conclusion is a kind of paste, or maybe synthetic spinel.


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 Post subject: Re: Help with suspected CZs
PostPosted: Tue May 18, 2021 12:34 pm 
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HenkRijneveld wrote:
I would go with the obvious. 144 diamonds with no LWUV reaction means no natural diamonds.
Only an uniform greenish color in SWUV should rule out HPHT. Why do you think it is CZ?

if these are synthetics or CZ the ring should sparkle like hell in light. You don't mention this and it is also not visible in your pictures (there is no fire at all).

Most logical conclusion is a kind of paste, or maybe synthetic spinel.


It does have sparkle but not the kind I'd normally associate with diamonds and it is lacking in some of the fire that I've seen in other simulants like CZ or glass but I was thinking that might be due to the size and the damage I'm finding on about 30% of the stones. Luster seems a little off as well.

That said what's putting it to CZs is the way it's looking through VO. It's a very typical CZ reaction from previous experience. I haven't seen a green SWUV from paste but that's probably the only other thing that would make sense here and the stones are just deep cuts pushing the primaries out to the edge where you normally see for CZ and it's dispersion would be relatively high from what I'm seeing. Spinel has too low a dispersion for it to match.

I'm getting in contact with another gemmologist in the next city over (about 200 km from me) that has a probe that should help identify them so I might just need to take a drive out there to confirm. I'll update when I have a positive confirmation. Thanks for the suggestions everyone!

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 Post subject: Re: Help with suspected CZs
PostPosted: Tue May 18, 2021 1:26 pm 
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Why does it have to be cz or diamond in all the reasoning? 10kt jewellery with colorless topaz, quartz and zircon is quite common in this type of piece.

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 Post subject: Re: Help with suspected CZs
PostPosted: Tue May 18, 2021 4:52 pm 
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Any maker's marks in the ring you could use to locate the original maker and research what kind of stones they normally use.... or give them a call.
Please post a pic of the entire ring.


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 Post subject: Re: Help with suspected CZs
PostPosted: Tue May 18, 2021 7:40 pm 
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glhays wrote:
Why does it have to be cz or diamond in all the reasoning? 10kt jewellery with colorless topaz, quartz and zircon is quite common in this type of piece.


No doubling of facets so unlikely that it's Zircon. I had thought Quartz as well at one point but after getting the VO on it it's very unlikely. The dispersion has to be 0.035 or higher based on previous experience and it looks to be SR so it rules both of those out. Glass or CZ would be most likely the answer.

Barbra Voltaire, FGG wrote:
Any maker's marks in the ring you could use to locate the original maker and research what kind of stones they normally use.... or give them a call.
Pleas post a pic of the entire ring.


I totally forgot to post a picture of the entire thing, sorry. Below are two angles, one with a makers mark of ALM which I believe is Almar (one of the vendors a local jeweller works with). Apparently they carried this ring about 15-ish years ago and most of the time if it was silver it had CZs in it and gold was usually set with diamonds (according to the jeweller).

Attachment:
IMG_20210518_170509.jpg
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Attachment:
IMG_20210518_170445.jpg
IMG_20210518_170445.jpg [ 860.29 KiB | Viewed 1020 times ]

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 Post subject: Re: Help with suspected CZs
PostPosted: Tue May 18, 2021 8:44 pm 
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Thanks for the further clarity. Sorry for making you repeat it, wasn't the intention.

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 Post subject: Re: Help with suspected CZs
PostPosted: Tue May 18, 2021 9:45 pm 
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Sounds like the problem has been solved.
Make sure you make a notation on the appraisal with the manufacturers information and also the local jeweler who supplied information.
At the end of my appraisals, right before the Errors and Omissions clause, I include
Additional Sources Consulted for Valuation and Replacement:

I would list both here.

In addition, there is a contact page for Almar jewelry in the Philippines.
Contact them. Ask if it is their design and what current replacement value would be on the ring.

https://almar-jewelry.business.site/
and
https://www.almarshellindustries.com/contact-us.html


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 Post subject: Re: Help with suspected CZs
PostPosted: Tue May 18, 2021 11:07 pm 
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glhays wrote:
Thanks for the further clarity. Sorry for making you repeat it, wasn't the intention.


No problem, it's the circle I've been going in already so I keep questioning it myself. The longer I look at these stones the more I flip flop between what they might be, I know it's something I did even when I was going through my gemmology course so I figure I just need a bit more experience as I'm doing it less now.

Barbra Voltaire, FGG wrote:
Sounds like the problem has been solved.
Make sure you make a notation on the appraisal with the manufacturers information and also the local jeweler who supplied information.
At the end of my appraisals, right before the Errors and Omissions clause, I include
Additional Sources Consulted for Valuation and Replacement:

I would list both here.

In addition, there is a contact page for Almar jewelry in the Philippines.
Contact them. Ask if it is their design and what current replacement value would be on the ring.

https://almar-jewelry.business.site/
and
https://www.almarshellindustries.com/contact-us.html


I'm not sure the problem is solved completely as this is gold but I'm doubting they are diamonds but it should be on Friday. I'm heading out of town to see what the other gemmologist will say on it after they can test it and see the ring. I'll post the final response when I have it.

I will be contacting the company though I don't think they're based in the Philippines, the jeweller here always gets his stock from Montreal but I know the building so I should be able to get a hold of them (assuming they haven't closed due to COVID) and if not the jeweller might be willing to give me a contact number for them. I appreciate the format though, I had an "other notes" section that I could use but I like that wording better so, if you don't mind, I'll adapt it to fit into my appraisals.

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 Post subject: Re: Help with suspected CZs
PostPosted: Tue May 18, 2021 11:56 pm 
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There is an ALM registered in Canada.
DBA:

Bijouterie Almar Inc
620 Rue Cathcart Bureau 760
Montreal, QC H3B 1M1
+1 514 874 0001


Most importantly, there is nothing wrong with turning down an appraisal when you don't feel you can or want to do it. Better to pass than be wrong.


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 Post subject: Re: Help with suspected CZs
PostPosted: Wed May 19, 2021 3:00 am 
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Just out of curiosity, how do you use visual optics in this situation to determine dispersion (I only learned to use it with light from behind the pavillion during a workshop with Alan Hodskinson on the FEEG symposium 2020, which is obviously impossible here)?

Just a random thought and long shot, the SWUV green could also be from an undisclosed adhesive which they used as a helper during setting. Very curious what the conclusion will be.


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