chrysoberyl chrysys

[VapidLapid]

Pictured here is a purported Chrysoberyl stone of 5+ carats.
What say you?

 

[Roger Dery]

Hi VL,
I believe it has great potential as a re-cut stone, but sure looks like a Zircon and not a Chrysoberyl.

 

[VapidLapid]

Exactly what I thought. A zircon, not a chrysoberyl. It is being offered by a vendor who has received good reviews here. Vendors are human too and can make mistakes. I doubt this is an intentional deceit. Just another example of why it is important to ask questions and verify.

 

[Lee Little]

A refractometer could give an RI on Chrysoberyl but not on a Zircon, would not take much to separate them. Maybe a typo as it would seem impossible to miss ID gems that are so different. Of course, that really may be a Chrysoberyl, I cannot see that it is not by the fuzzy photos. What are the exact dimensions and the exact weight? We could separate them easily by the math as well. Best regards, Lee

 

[chrono]

Maybe it's just me but the stone looks to have double refraction which chrysoberyls do not exhibit. Or perhaps the camera is so shaky that it shows double images.

 

[Kismet]

A refractometer could give an RI on Chrysoberyl but not on a Zircon, would not take much to separate them. Maybe a typo as it would seem impossible to miss ID gems that are so different. Of course, that really may be a Chrysoberyl, I cannot see that it is not by the fuzzy photos. What are the exact dimensions and the exact weight? We could separate them easily by the math as well. Best regards, Lee

They have the measurements as 8.8 x 8.1 x 6.7 and the weight at 5.22 cts.

 

[RockHugger]

Looks like zircon. The 3d pic the crown is clear but pavilion is double immage. So it's not a shaky camera!

 

[Arcadian]

It also looks like a zircon to me too. So I'm going to ask a dumb question (bear with me here)

Could Chrysto actually have this buttery yellow color? Generally when i've seen 'yellow' chrysto its also had green in it.


-A

 

[Roger Dery]

It also looks like a zircon to me too. So I'm going to ask a dumb question (bear with me here) Could Chrysto actually have this buttery yellow color? Generally when i've seen 'yellow' chrysto its also had green in it.

Hi Arcadian,
It is possible that Chrysoberyl can have the 'buttery yellow' color, but it is seldom seen. The give-aways are:
a- the serious doubling of the pavilion facets as seen through the table
b- along the crown / girdle line junction there is some obvious 'chipping' that is so typical of Zircon, and non-typical of Chrysoberyl
c- the significant weight for the measurements provided (Zircon having a SG of 4.7 or so, and Chrysoberyl at around 3.7)

Hope you find this helpful.

 

[RockHugger]

Is this a tan stone?

 

[Arcadian]

It also looks like a zircon to me too. So I'm going to ask a dumb question (bear with me here) Could Chrysto actually have this buttery yellow color? Generally when i've seen 'yellow' chrysto its also had green in it.

Hi Arcadian,
It is possible that Chrysoberyl can have the 'buttery yellow' color, but it is seldom seen. The give-aways are:
a- the serious doubling of the pavilion facets as seen through the table
b- along the crown / girdle line junction there is some obvious 'chipping' that is so typical of Zircon, and non-typical of Chrysoberyl
c- the significant weight for the measurements provided (Zircon having a SG of 4.7 or so, and Chrysoberyl at around 3.7)

Hope you find this helpful.

Very helpful, thanks Roger!

-A

 

[Lee Little]

A Chrysoberyl that size should weigh about 4.25 carat.
A Zircon with those measurements should weigh about 5.35.
For girdle thickness I added 2% and for the bulge factor I figured 12% but I would bet that is a bit too much on the bulge. Sure looks like Zircon by the math and cannot be Chrysoberyl by my math.
The color could be Chrysoberyl but this time it is probably not. Best regards, Lee

 

[T L]

It could also be sphene which is highly double refractive.

 

[chrono]

It could also be sphene which is highly double refractive.

It could be but I’m not seeing any dispersion at all in the pictures.

 

[brandy_z28]

I'm thinking sphene too. When I look into my sphenes they definitely have that hazy hallucinating look, moreso than the zircons that I own. Could be either but sphene is my first guess with zircon being my second.

 

[brandy_z28]

It could also be sphene which is highly double refractive.

It could be but I’m not seeing any dispersion at all in the pictures.

I see hints of green and orange areas that look like they could be dispersion, it just wasn't captured well.

 

[tsavvy]

Sphene has a lower specific gravity than chrysoberyl, so it would weigh even less. Higher SG = greater weight, lower SG = less weight.

 

[Lee Little]

Good guess, it does look like Sphene also but by the math with the dimensions a Sphene would weigh only 4.00 carats. Re-cap, Chryso would be 4.25, Zircon 5.35. It actually weighs 5.22. The math is usually accurate within 10%. So far that only leaves Zircon on the 3 I have checked as being a possibility. Best regards, Lee

 

[T L]

It could also be sphene which is highly double refractive.

It could be but I’m not seeing any dispersion at all in the pictures.

Sometimes it's hard to capture dispersion on camera, especially if the stone is sleepy. I don't know if it's sphene, just throwing that out there because you never know.

 

[davi_el_mejor]

What about YAG and a shaky camera?

 

[RockHugger]

That still doesn't explain the math....

I agree, math leads to zircon Unless they messed up on the measurements too.

 

[Lee Little]

What about YAG and a shaky camera?

Sure can't be ruled out by the math, YAG would be 5.15 carats.

 

[LD]

I wouldn't even begin to make an identification as the photos are far too blurry!

I can safely say that it's a yellow stone. Does that help?

 

[Lee Little]

Yes, Loving Diamond, that does help as it made me laugh! Thanks for your input, best regards, Lee

 

[VapidLapid]

I emailed the vendor and he said that he remembers thinking the same thing when it came in, but that the source for the stone said chrysoberyl and even that it was cut from an adjoining crystal as the other chrysoberyls (that it came in with). All the other chrysoberyls I saw on the site were typically greenish yellow and did not have the birefringence of this one. I wonder if that adjoining crystal was a zircon guilty of chrysoberldom by association? Or perhaps it is an ultra rare form of chrysoberyl, maybe one with multiple twin crystals inside that torques the electron angles between atoms in the lattice so strongly that that material becomes birefringent and that the atoms are packed tighter making the specific gravity differ; some sort of isomorph on steroids. Or maybe its a zircon that grew next to a chrysoberyl.