Golden Beryl sold as Yellow Sapphire

[qtx2]

Date: 2/25/2008 3:55:38 PM
Author: Michael_E
qtx2,

This is sort of an interesting way to approach this, but what the heck, I''m up for anything. There are several problems here which are apparent, not even to you, qtx2. The first of which is that I am not physically able to meet with you, due to a series of ongoing family problems. I am able to work via the internet only and generally avoid the phone since it keeps me from having a record of exactly what my clients want. (Anyone wanting further details on the problems which have caused this circumstance can certainly write me...please expect something akin to a bad novel in response).


The other problems with this deal involve getting the stone back to me. I obviously can''t do anything without the stone and I can''t have the stone in the setting, (and neither can whoever did the appraisal), since the prongs on that ring make it impossible to do an accurate Refractive Index test on the stone. How did your appraisers do that test anyway ? In any case, please do send the stone back to me,(if it''s in the setting that''s fine, but I''ll need to remove and replace it), and if the stone turns out to be a golden beryl, not a sapphire, then you have the 3 options which I mentioned in my e-mail to you.


If you''re concerned about me being able to cut a replacement stone to the exact dimensions of first one, (assuming that the stone is not a sapphire), please don''t worry about it. I''ve been at this for a long time and can cut to about 1/10mm and fit anything. I hope that this helps a bit qtx2, please let me know what you want to do.


Oh, a word of advice to others who are buyers of loose gems, please do get an appraisal on the stones that you buy before you set them and as soon after you buy them as possible. This makes it possible for an appraiser/gemologist to accurately test and inspect the stone, before you have it set. Getting this done shortly after your purchase also makes it much easier to send it back if it doesn''t suit you and avoids this problem of fitting a new stone to a custom setting.


Have a great day all !

Michael, I''m very sorry to hear about your family problems. I had no idea and I hope everything works out for you. About the RT test, the two appraisers put the ring/stone face down on the machine. If what you say it''s true (the prongs may contribute to an inaccurate RI reading), then perhaps it may had since putting the ring face down the prongs would''ve elevated the stone. My question is this, is there any way to accurately test the stone without disassembling the ring? We now know that an RI test is not sufficient enough (assuming that the stone is a sapphire), is there any other tests that could be done by a gemologist/independent appraiser to accurately examine/appraise the stone?

 

[The Joker]

Interesting Thread!!

My two cents.

Beryl:
Refractive index = 1.57 - 1.60
Hardness = 7.5 - 8.0
Density = 2.7

Corundum:
Refractive index = 1.76 - 1.77
Hardness = 9.0
Density = 4.0

The difference in the RI of the golden beryl and the yellow sapphire is not great. But the difference in density is great and would be easy to test if the stone were loose.

Joker....

 

[jeffwhite]

Date: 2/26/2008 10:53:56 AM
Author: The Joker


Interesting Thread!!

My two cents.

Beryl:
Refractive index = 1.57 - 1.60
Hardness = 7.5 - 8.0
Density = 2.7



Corundum:
Refractive index = 1.76 - 1.77
Hardness = 9.0
Density = 4.0



The difference in the RI of the golden beryl and the yellow sapphire is not great. But the difference in density is great and would be easy to test if the stone were loose.

Joker....

On the contrary, the difference in RI between beryl and sapphire is actually considered very large and is easily discernable with a refractometer. I sometimes recut spinels and can consistently distinguish synthetic flame fusion spinel (RI ~ 1.73) from natural spinel (RI ~ 1.717-1.72) by RI.

Also, I don''t quite understand the assertion that the stone must be loose for an RI determination to be made. If the stone can be placed table-down on the refractometer, an RI determination can be made. The only limitations to this are if the prongs/mount are the same height or higher than the table (thus preventing intimate contact). Sounds like this is what your labs have done, and it is perfectly acceptable. One just has to be very careful not to scratch the soft glass of the hemicylinder with the mount

Best of luck to you. I hope everything works out....

 

[Pandora II]

The only way I can see that they could tell for definite is either using the SG - a 2ct sapphire will be a lot smaller than a 2ct golden beryl, or by the RI - which is definitely different enough to clearly see the difference. 1.563-1.583 versus 1.757-1.778.

Looking at the setting on Maytal''s website, I can''t see how they could have measured the RI properly as the mounting would prevent contact between the table of the stone and the glass.

I would be a bit surprised is someone could tell just by looking - helidor is not very included normally also, both stones would be doubly refractive, but the birefringence is very close.

Maybe someone more knowledgeable will know if there is a way of estimating the SG through knowing the carat weight and the dimensions of the stone?

 

[strmrdr]

Michael sorry too hear about your family problems.
Hope they get resolved soon.

At this point I think I'd just send it too Michael too find out whats going on.
I had a very good buying experience with him and he was honest and up front with me.
I have some custom cutting projects on the back burner that he will eventually be cutting for me.

The only other option I would consider is having Rich Sherwood take a look at it.
He is my go too gemstone expert.

 

[CaptAubrey]

I''m intrigued that no one has mentioned visible absorption spectrum. Yellow sapphire typically shows 1-3 lines in the blue region or, for Sri Lankan material, strong apricot fluorescence--neither of which you see in golden beryl, which is never fluorescent and may show only an indistinct band in the same area. I wouldn''t bet my life on this criterion alone, but it would be useful evidence when combined with other observations.

There are also ways of estimating RI on mounted stones, one of which is the visual optics method mentioned above. To someone experienced with it, especially someone who has reference stones for comparison, it is possible to separate beryl and corundum.

I have no idea what these two appraisers did, but the refractometer alone is not the only way of doing this.

 

[elmo]

Date: 2/27/2008 3:05:23 PM
Author: strmrdr
At this point I think I'd just send it too Michael too find out whats going on.

I disagree. The OP wants an appraisal for their engagement ring. Let's say Michael has a look and says I don't know what these other two folks were thinking it's sapphire. Even if the OP has zero lingering doubts after that which would be perfectly reasonable with a trusted seller, they're still unable to get the appraisal they've paid for, twice.

So the Richard Sherwood option works better in this case. However if they got a low cost AGL ID report they could simply go back to one or both of their original appraisers and ask that they update the report they already bought. I expect this gives a good result and costs less. Edit, I take "costs less" back if the stone has to be unset.

 

[Mrs Mitchell]

Michael, I just wanted to say sorry to hear of your family problems. I too hope they can be resolved soon.

Jen

 

[desertgem]

Hello all,

Just wanted to say after looking at the mount, that I doubt any
knowledgeable gemologist would put that ring on a glass hemicylinder
of a refractometer, and I doubt it would read reliably on a reflectivity
meter either, due to the rather high prongs on the setting. Since prongs
were designed into the setting it would appear to me that the stone was set
and held by them, and that any capable setter could loosen them to free
the stone for a definitive R.I. test. Photos and precise measurements to
hundredths of mm and caratage could be validated by the jeweler, and then the
stone sent to the cutter for examination. The setting does not appear to be
a cast-in-place type at all.

Also someone asked about a way to estimate carats from dimensions, etc. The
one I use is http://dendritics.com/scales/carat-weight.asp which has many
different parameters.

Jim