Ruby information

[Mr Magoo]

Sapphire Heat and Pressure Treatment 5 of 5

https://www.prospectingaustralia.com/forum/doc/member-docs/3008/1549879924_heat_and_pressure08-10.pdf

 

[Dihusky]

Hmmm, need some time to digest this, certainly specialised gear to do 1500C+ at 900bar, not for the back-yarder!

 

[Theduke]

So that sapphire is a heat treated dyed one ?. Once I get my act together and get the other photos to show what I was originally talking about Ill post them. As for the inclusions in the last ruby I will need to study them a bit more in different angles so I can clarify their exact nature as they can be a couple of things. Sorry for the misslead due to tired brain and late night of posting, I will come back with the information I was originally trying to convey once I can get the focussed photos that correctly correspond with the info. I will also cover the dark inclusion in the last ruby

 

[Theduke]

As for heat treatments only, its more accepted in sapphires than it is in rubies. As theyre the same family it shouldnt be such a big difference but is.

If youre able to get a completely untreated stone that looks good at a decent price its worth it even if the cut is ordinary. In most cases youre able to value add by getting the stone precision cut and while losing some carat weight.

 

[Mr Magoo]

One of the ways to check if a bubble is air (gas) is to view it in 'dark field' lighting. Apparently, if gas, the bubble will be black. I haven't done this so can't verify it. But Dihusky may be able to confirm that being a photography bloke.

I'm no expert, not even close, but do a bucket load of reading on GOL and download any papers that turn up there and have done for years. (I found that paper I just posted, on there today just while rummaging around for anything interesting)

So that sapphire is a heat treated dyed one

I'm 'suspecting' it's filled with cobolt blue glass. Somewhere I have a similar image, if I find it I will post. So the blue of the glass adds the colour to the stone.
I (personally) just don't believe the stones have just been heated for clarity or colour. That pdf I put up shows pretty much the evidence I know of, stress (tension) fractures and crystal alteration. The lines do not mean they have been filled but bubbles is evidence and also blue flashing (which is in the video that's linked to post #5).
To me that looked present in some of the images but didn't comment earlier as it's so hard to tell from an image. But you may know as you have the stone with movement.

And please don't take what I say as gospel, I'm just basing it on personal reading/study I have done but the evidence is pretty consistent. I just haven't come across the lines theory before. So interested in what you have.

No need to apologize for anything. You may be right and anyway that's what forums are for. It far more interesting when a thread like this is started, it always gives food for thought. :Y:

 

[Mr Magoo]

As for heat treatments only, its more accepted in sapphires than it is in rubies. As theyre the same family it shouldnt be such a big difference but is.

If youre able to get a completely untreated stone that looks good at a decent price its worth it even if the cut is ordinary. In most cases youre able to value add by getting the stone precision cut and while losing some carat weight.

Totally agree. Same goes for other stones like Tanzanite. AFAIK Tanzanite has to be cut in Tanzania if over a certain size. This bloke is selling large cut Tanzanite as preforms and if you look at Tanzanite ct value to the price of these stone you could make a good dollar (he has a good reputation). If you're confident. A bad day if you get it wrong though. :argh:

https://africangemstones.us/preform-tanzanites/

 

[Mr Magoo]

I think you will find this interesting. What's your thoughts?
Not the image I was after but this was easier.

http://www.ruby-sapphire.com/glass-filled-sapphire.htm

 

[Dihusky]

I'm not going to try and explain as I have never done dark field illumination intentionally, yet have achieved similar results using what we used to refer to a 'rim lighting'. Kind of accidental understanding The image I posted here of the tubes is a bit like dark field, the black background is what makes it work: https://www.prospectingaustralia.com/forum/viewtopic.php?id=28731

I think this explains it well with some stunning images. I definitely want to play with this and make a small rig for photographing cut jems.

https://www.mindat.org/article.php/...Illumination+for+Mineral+Specimen+Photography

Might grab a length of low powered LEDs and have a play, the rig is pretty simple but I think one needs to add rings of LEDs judiciously, too many and the effect is lost as you end up with too much light on the front of the specimen. Thinking a 50mm length of white PVC downpipe and two wraps of LEDs might be a good starting point for a small object. The white area above the LEDs might provide enough front lighting, but if it's too much a ring of black paper slipped inside the tube will fix it. Also need to be able to vary the height of the specimen inside the tube.

Better go ferreting

 

[user 4386]

Interesting. Of course the intensity of fluorescence in natural or synthetic rubies is less if they have a high iron content. Inclusions etc are very useful. I am a bit doubtful that you can tell a Burmese ruby by its fluorescence - I suspect that it is more a case of you can tell a ruby that it is unlikely to be Burmese (i.e. because Burmese rubies fluoresce similarly to each other). However there are probably even limitations on that - rubies come from a number of different localities in Burma.

 

[Theduke]

Its the quickest way to tell once you know what to look for. Heres a exert from a identification paper, unfortunately photos dont always show exactly how something will look to the eye but can be handy.

Here is an overview of how some rubies fluoresce under longwave (LW) and shortwave (SW) ultraviolet light.

Myanmar (Burma) Rubies: LW strong red. SW moderate red.
Sri Lanka (Ceylon) rubies: LW strong orange/red. SW moderate orange/red.
Thai rubies: LW weak red. SW inert.
Flame fusion rubies (synthetic): LW very strong orange/red. SW moderate to strong orange/red.
Flux grown rubies (synthetic): LW Strong orange/red. SW orangey red and may have a blue tint or areas of blue.

Once I can get the clear photos of the other inclusions to look for that are helpful to determine the origin Ill put them up unfortunately its a frustrating process trying to get a clear photo of something so small 8.( :lol: :lol:

 

[Dihusky]

Without worrying about the technicalities of UV, SW UV is still a powerful discriminator when buying stones in the orient, fastest way out of the garnet con which is common for the unsuspecting buyer

 

[Theduke]

Without worrying about the technicalities of UV, SW UV is still a powerful discriminator when buying stones in the orient, fastest way out of the garnet con which is common for the unsuspecting buyer

Heres a ruby and garnet bracelet that shows this. Photo was taken in daylight so no need for any dark spaces either

 

[Dihusky]

:inlove: that has to the most perfect example :Y:

 

[user 4386]

"rubies from other sources also can possess the strong red fluorescence and silk comparable to those sourced in Myanmar (formerly known as Burma)"

"the material from Mozambique varies in iron content, so its rubies can have a fluorescence and color hues in similar to the classic colors of Burmese rubies, according to gemologist Richard Wises Secrets of the Gem Trade (Second Edition). In his book, Wise wrote that he has seen several stones from Mozambique that rival, in hue, saturation the best Burma has to offer.

https://www.nationaljeweler.com/blog/5071-5-things-to-know-about-burmese-rubies

Hold the stone directly in front of your eye. The stone should be as close to your eye as possible without actually touching your eye. Move the stone toward the light. Roll the stone around slowly between your fingers. Examine the light patterns that result within the stone. If you are holding a true ruby, you should see a rainbow pattern emerge in various shades of red and blue. A garnet, however, will display a rainbow pattern that contains greens and yellows. Look for double rainbows. A ruby is a doubly refractive stone, so it refracts light in a much different way than a garnet, which is singly refractive. If you are holding a ruby, the rainbow image you see will be blurred and appear almost as one rainbow on top of another. The rainbow image you see within a garnet will be much more clear due to its singly refractive property.

There is no magic bullet without using a polariscope, although even these may not be ideal for ruby and garnet.

http://gemologyproject.com/wiki/index.php?title=Polariscope

It is the high iron of red garnets that prevents their fluorescence, so this is a fair test for distinguishing ruby and red garnet.

 

[Theduke]

Heres a table of testing that GIA did on Mozambique ruby. As you can see swuv is what would destinguish where a ruby is from if there were rubies showing similar fluorescence under a uv light. It all comes down to the iron content and the host rocks where the rubies are found