I've obtained a rather large (I won't say how large just yet) cushion cut yellow sapphire. I've sent pictures of it around to several noted cutters because I want to have it recut. One cutter, in a very kind manner, told me he thinks the stone is a synthetic based on the criteria I gave him. ANother cutter wrote back and thinks it's natural. The supplier swears it's not Be heated and is a natural stone. What to do? I need to send it to a lab for verification that it is a natural and not a synthetic. But I also need to find out if it's be heated. Personally I am pretty sure it's natural because it has a couple of silky veils.

The question is where do I send it to have both of these things done? And how much can I expect it to cost me? Should I stick to the BIG THREE? Or are there smaller labs who can do the job for less? If the stone is real it's gonna be recut so I don't want to spend an arm and a leg on a cert when I'll have to do it all over again after cutting.

Any advice will be appreciated. To satisfy your curiosity here are a couple of pics of the stone:





Thanks,

Jason

Hi Jason

If its BE treated it will probably have a "rind" and recuting will probably leave you with a vry funny looking stone.. hope its not good luck

Oh sorry not really up on the labs

Wolf,

My supplier swears it's not Be heated. Harumph. He also happens to be Thai. Nuff' said.

Jason

Hello,
"Halloween" or "not Halloween"?
My advise in this case is to "get the stone drunk" as "drunk stones" will be more likely to speak after a "beryllium party" in a furnace near the beach in Thailand.
LOL

Yellow to orange sapphire looking like that were usualy heated with or without beryllium (I've seen both), but unheated stones with this color are also possible: They are called "Fanta" sapphires near Andronbomifehy in North Madagascar or "Busarakam" near Chanthaburi in Thailand. They may also be mined in other places producing basaltic sapphires like Vietnam or Australia.

If with a microscope some sign of heat treatment can be found, then you can try to see if the stone was or not heated using additive like beryllium. To do soo it is a good idea to immerse the stone in a liquid which RI is as close as possible from the stone RI: Methylene Iodine is usualy best, but oil or even alcohol can be fine enough and safer if you use a vertical microscope with a bulb producing a lot of heat. While on fieldtrip with students and friends, of course it is difficult to use methylene Iodine but Vodka can be found...
So put the stone under immersion in an immersion cell and use a filter to diffuse the light from a very strong light source (like a microscope bulb) and study the stone color zoning:
If you can see any "orange color rim" or some curved or "splashy" orangy areas then as one of my student one day said: "It's Halloween!"... It means that probably the stone have been heated using beryllium heat treatment technology.

Now if you want to be sure about that, you will have to send the stone to a lab providing LIBS or better LAICPMS services.

Hoping to have helped and have some fun with your "Halloween" experiment party!

All the best,

Hi Vincent,

Immersion is a good technique for surface diffusion, but, in the case of Be diffused stones where the penetration is more complete, will this be indicative of any color Be diffused corundum other than yellow/orange?

Making conversation. It's a good thing for everyone to know.

Good question JB a grey area in my mind.
Jason,you should be able to get someone to just advise if they think its been heated,if so has it been high temp. My understanding BE need high temp over normally longer time,this is normally evident under microscope inspection. You should be able to negotiate a price for just this verbal advice and not worry about a actual cert.

Andrew,

Thanks for the tip. Question, the stone has a couple of slight silky veils. If it has been high temp heated is there a higher likelyhood that these veils would have dissolved?

Thanks

Jason, you have worded it correctly,there is certainly a higher likelyhood that these veils would have dissolved, but not enough to rule it out,those veils or inclusions under magnification should reveal its past.

Hello,
Beryllium will affect the natural color zoning of a stone, the fact that the diffusion is "complete" does not mean that nothing will be noticeable. With experience using immersion in some cases it is possible to find some indication of beryllium heat treatment in yellow orange sapphires especially if the stone had originaly some very strong color zoning. To answer JB, Immersion is the best technique to study all types of color zoning in gems, not only "surface diffusion", but it is most of the time giving only some indicative information.

This is a small flat stone before and after heat treatment with beryllium, the diffusion can be told as "complete" as the stone is both flat and small. You can nevertheless see that it you cut a stone from this rough you will not have a "rim" but you can see some combinations of colors/color zoning which are very suspicious in a stone heatead without beryllium.





The color zoning in beryllium treated stones does not just follow the shape of the stone but it is first very dependant of the local chemistry of the stone: Blue is usualy not homogeneous (as Titanium is usually not homogeneous in a sapphire) and this is the same for colors centers. You can then have some pink and orange whihc does not follow the shape of the stone and also at the same time havbe a rim like in the following:



In that stone you can see the color rim you imagine for Beryllium treated stones, but you can see also a large patchy orange patch due to the natural color zoning of the stone whihc was affecte by beryllium and in the center some blue patches due to former rutile silk. (The blue is visible as there was not enough Beryllium to neutalize all the Titanium which has internaly diffused from the former rutile silk inclusions...)
It shows that color zoning in the case of beryllium treatment depends largely on the "natural color zoning / chemistry" of the stone.

Now you can find silky clouds in a stones heated at "high temperature" with beryllium or not: May be the stone was too silky and everything was not dissolved or possibly it was not cooled rapidaly enough and some clouds have formed again around 1200C.
Many stones heated at "high temperature" remain cloudy all over the stone or in some areas with design like "paint brushes".

Note: Of course and I repeat, observation under immersion has to be taken carefully as it is an indicative method useful for experienced gemmologists to ring a bell. If you dont have that experience, my advise is to bring the stone to a good gem lab.

Hoping to have helped,

All the best,

Great info again Vincent!
Jason as you no Gemology is a matter of detective work,put all the clues together add knowledge and equipment and achieve the most likely outcome.
You no the size,colour,clarity and the Price. These are also relevant,no one will give away a large unheated Gem thats attractive.
just my 2c worth
cheers Andrew

Thanks again Vincent!
unfortunately in my recent experience i've not seen the rim or the core in no one ruby i've checked.
it's since some months that double treated rubies are hit the market here.
i've seen many stones be-treated and then glass filled but, except for high temeprature signs and flash effects no one showed other in immersion like your beautiful pictures shows. Maybe i was unlucky
just my 2cent

Alberto

oops i've forgot an answer: Vincent, at Gubelin lab which kind of device you're using to detect be-diffusion? LIBS, LAICPMS or SIMM?
For what i know here in Italy we have only one lab (cisgem) which can detect be-diffusion but have no idea on which method they use. i've read on G&G for the comparative tests so, i'm interested. Your answer could be important for some friends of mine to choose the right lab for suspected stones

cheers

Alberto

Dear Alberto,
The Gubelin Gem Lab has invested in "Laser Ablation ICPMS". The main reason is that this instrument has much more applications than LIBS. It is useful also for origin determination of emeralds, "Paraiba tourmalines", etc...
Reagarding sapphires, LAICPMS is also more powerful than LIBS as an exemple, regarding Beryllium in blue sapphires, most of the time LIBS can only provide you the information that there is or there is no beryllium. To my knowledge, except when there are some inclusions quite typical of heat treatment at "High temperatures and/or long time", LIBS cannot help to separate stones containing naturaly Beryllium which have been heat treated with stones treated with beryllium...

Re



Regarding rubies you are right, it is quite different, but I was answering here a question about yellow or orange sapphires. For rubies in some cases you will find a yellow or orange rim around the girdle when you immerse the stone in methylene Iodine, but I suspect that some burners succede in reducing this rim with one more heat treatment process. But one thing you can notice and which should ring a bell is that usualy rubies are heated at lower temperatures than yellow sapphires. So rubies with unusually heated inclusions should be noticed. Rubies heated with beryllium are usualy stones from Songea, or basalt related rubies like Thai or Madagascar rubies. In this case some studies on their specific inclusions can be useful to get easier with them.

Now you are now telling something which sound "funny" to me: Rubies heated with beryllium and then glass filled? Usualy the beryllium treatment is performed also with some flux like possibly borax. It mean that after treatment the fissures will be closed and the cavities filled. You may also find some synthetic overgrowth. The thing which is surprising is that after such treatment there is no open fractures anymore, so I dont see any reason and any possibility to performe a glass filling...
Are you sure that these flashes are glass filling flashes? Nevertheless I know that two years ago some people were working on a treatment mixing some kind of high refractive index glass like flux. The few stones I saw were looking very similar to stones heated with more standart "borax type" process.
Nevertheless, it is still possible that something new is coming... Anyway I would be curious to see one of these stones you are telling about.
Hoping to have helped.
All the best,

Dear Vincent,
i'm happy that your lab has invested in LAICPMS for ALL the reasons you've well explained. i will take into consideration .
Regarding the rubies i can only say what i've observed: strong heated, crystals almost completely melt (BTW, my avatar shows a partially melt corundum crystal coming from a stone of this kind ) and... blue-blue/yellow flashes typical of lead glass filled. i've got no other sophisticated instruments to perform more specifical test but my personal experience and my eyes through a B&L stereozoom 7.
I don't know if a flux like borax can shows flashes of the same aspect/color like the lead glass do. If you can confirm this i'll be happy to have put another brick in the wall.
thank you very much, again.


Alberto

One funny thing about your comment that may also interest you: In most of the lasted lead glass filled rubies currently available in Bangkok, the blue/orange flashes are nearly impossible to see.
I started to see such stones around 6 to 8 months ago and they seems to be more present now.
The explanation seems to be that the burners and the chemical engeneers they are working with are still improving the chemical composition of the glass they use in order to minimize these flashes and also to minimize the number of gas bubbles. It seems that they are not ass succesful with the bubbles as they are with the flashes as the last stones I saw had still flatened bubbles but nearly no flashes.
All the best,