Cat's eye Sapphire conclusion?

[Stephen Challener]

You never know. I thought that I wouldn't see a purple beryl until my dad got one on the cheap on eBay. Sometimes sellers have no idea that what they have is unusual or exceptional--if you happen to have your eyes open at the right time in the right place you might just strike paydirt.

[Barbra Voltaire, FGG]

If anyone will stumble on this, it will be you and/or your dad. I'll be waiting.

[Christopher P. Smith]

Hello all,
Cool thread for a pretty cool stone. You are all right in that the top of the cab was cut perpendicular to the c-axis, so that only one leg of an asterism could be seen. This stone was actually quite interesting in that the top portion of the stone was quite flat, so the other legs were not visible, even from the side.

If our client gives us permission, I'll post the photo.

Cheers and Season's Greetings,
Christopher P. Smith

[LiYou]

Hello all,
Cool thread for a pretty cool stone. You are all right in that the top of the cab was cut perpendicular to the c-axis, so that only one leg of an asterism could be seen. This stone was actually quite interesting in that the top portion of the stone was quite flat, so the other legs were not visible, even from the side.

If our client gives us permission, I'll post the photo.

Cheers and Season's Greetings,
Christopher P. Smith

Well, I do not mind if you post the photo. The problem is, I asked Brad (the vendor) to send the stone to you. Since this is the case, I think Brad is your client instead of me. I will get the stone sometime next week, I can post the photo of the sapphire brief.

Anyway, Thanks for the explaination guys

Honestly, I prefer you put star sapphire in the report than cat's eye sapphire. Fortunately, I bought this stone for my client who is looking for cat's eye sapphire. It saves me the hassle in finding another cat's eye sapphire. Btw Cris, do you allow me to use your post above the explain facts of the stone to my client?

[Christopher P. Smith]

No problem. Feel free, there are some very good comments made by others as well, which are more informative...

Personally, I think the stone is much more unique as a cat's-eye. I have seen countless star sapphires, but only a few stones that I would consider classifying as a cat's-eye sapphire.....

And the submitter is our client of record, so they would have to give us the permission.

Best regards,
Christopher P. Smith

[LiYou]

No problem. Feel free, there are some very good comments made by others as well, which are more informative...

Personally, I think the stone is much more unique as a cat's-eye. I have seen countless star sapphires, but only a few stones that I would consider classifying as a cat's-eye sapphire.....

And the submitter is our client of record, so they would have to give us the permission.

Best regards,
Christopher P. Smith

Honestly, I surprise that you know that stone I am talking about. I believe you test a lot of stone per day, yet you remember the details of my cat's eye sapphire

[roshanravan]

Honestly, I surprise that you know that stone I am talking about. I believe you test a lot of stone per day, yet you remember the details of my cat's eye sapphire

i was thinking the same, i don't even remember what i ate last night for dinner!!!!!
we are lucky that there is actually some one available from a famous lab here to answer our questions. Christopher always answers thorough and with patient.

[arms]

Heres one.. maybe

[1bwana1]

I have seen stones like this before. They are interesting and unusual.

One thing I notice is that the report says heated, yet the asterism remains. One of the reasons for the paucity of fine color star corundum is that during high temperature heat treatment the Rutile silk in the stone is melted, and the trace elements absorbed improving the color of the stone, but removing the asterism in the process.

I am assuming that your call on heat is for a low temperature heat treatment? Possibly to lighten the color rather, than create the blue color, or increase the saturation. This seems more likely because the rough appears to be shaped so that a star was not possible, yet the silk was preserved.

Any comments on the heat treatment?

[arms]

Apparently, the seller told me it is unheated and i asked him to get a GIA report, he was very upset it came back heated. He was quite sure its unheated. I noticed the cats eye sapphire afterwards on the cert. Its not a very strong cats eye and it was all by chance. Seller never noticed it. I thought it was neat thats its a cats eye so i bought it.

[Barbra Voltaire, FGG]

Arms, please report back with what you have found when the sapphire is viewed from all directions.
Thanks

[arms]

Will do. Its gotta be shipped back so may take a bit.

[1bwana1]

Apparently, the seller told me it is unheated and i asked him to get a GIA report, he was very upset it came back heated. He was quite sure its unheated. I noticed the cats eye sapphire afterwards on the cert. Its not a very strong cats eye and it was all by chance. Seller never noticed it. I thought it was neat thats its a cats eye so i bought it.

Most time when I see a stone like this it is unheated. That is why I was asking what indicated the heating. Only low temp heat treatment would normally leave the silk that cause the cats eye effect.

[arms]

Yes. Right. Is it possible the low heat could be caused by the dopping before cutting? The seller was quite sure its unheated.

[glhays]

I would not think that dopping heat would even be detected by the GIA. If that were the case almost all will be considered heated on the reports. Takes a great amount of heat to burn silk in corundum, something like 1850 °C, not sure if that is completely accurate but somewhere in that range. So anything below that might be done just to try and effect color.