Heated Rubies Confusion

[DiaLuv]

I am confused on heat used in rubies. I read that it is industry standard and ok.

But then I read GIA reports that have “heat treatment (minor, moderate residue)”. Is the residue filling in cracks caused by heating? If so, I thought vendors must state filling was used.

Thank you.

 

[Avondale]

I was looking into it myself fairly recently because it really is confusing and the trusting PS search wasn't especially helpful on this occasion. There might be some detailed explanation buried somewhere here in this forum but I couldn't find it. In the end I stumbled upon some useful information in the Gem-A online lectures. They're on youtube and I've found two are relevant in particular - "flux healed ruby" and "lead glass filled rubies and sapphires". You can check them out, just be prepared to have a couple of spare hours to watch them.

Here's the gist of it:

1. Heated only is pretty self-explanatory. The gem is treated only with very high temperature, nothing else.

2. Heat with flux means the gem is heated in the presence of another element (in rubies' case - borax). This element melts, enters into all of the gem fractures and dissolves their inner walls. Effectively dissolves the corundum. Upon cooling off the fractures are healed because they've been filled with newly formed corundum. However, there's also some residue from this process - this is the residue that's detected and mentioned in the certificate.

3. Glass filling again uses heat, but this time the gem's fractures are filled with lead glass. It's a matter of straight up "let's fill it up so it's less noticeable". When there's glass filling, this is also usually the term used - glass filled, lead glass filled, fracture filled, something-filled in general.

There are other treatments of course, but I'm mentioning glass filling specifically because... well, it's the main source of confusion.

As you know, 1 is widely accepted, stable, commands highest price after untreated rubies. 3 is very much not accepted, has a devastating effect on the price, is not stable and the gem is very fragile. 2 is stable, but it also has degrees of just how much of it there was. You start with insignificant, then there's minor, then moderate and I think it ends with flux-healed. All of those with their respective effect on price, of course.

Whether one is willing to accept some degree of residue is entirely up to personal decision. Only you know how much you'd be willing to compromise. Just gotta be careful not to overpay.

A necessary disclaimer - it's been a while now since I watched the Gem-A lectures so my comment might not be entirely accurate. I do recommend sparing the time to watch them, if you can - I found them very entertaining. I also can't advise on price or the meaning of whatever terminology labs use - still haven't reached this far into my "education".

 

[DiaLuv]

Avondale - thank you for your help. You explained it very well.

 

[Bron357]

The problem with rubies is that they are highly desirable and sell for high prices so people are inclined to use treatments to improve the look and therefore increase saleability and price.
Gems that look beautiful without any treatment are rare.
Most rubies have a lot of silk, that’s rutile inclusions that make them look cloudy. Some rubies even have blue (sapphire) zoning or spots (Burmese Mong Hsu) and heat dissolves the rutile needles making the ruby more transparent and heat removes the blue zoning in Mong Hsu rubies.
Just heat is acceptable.
However rubies are also found in less than desirable hues and often with internal fissures aka cracks within the ruby. Such rubies are unattractive and have very little value. With the wonders of modern technology these otherwise valueless rubies can be high heat treated, beryillum diffused and/or glass(flux) filled to make them look beautiful. And worth a lot more money!
The problem with treatments is that some, flux filling, aren’t stable and if they aren’t disclosed you could be spending $5,000 on a ruby worth $50.
That’s why you need a lab report, to know what level of treatment has been applied and therefore if the ruby is worth the money being asked.
To “look” at a ruby you can’t easily tell if it’s natural unheated, natural with heat, natural with high heat / BE / glass filling or lab grown. However the prices are widely different - up to $20,000 a carat for unheated Burmese down to $50 or less for lab grown.

 

[DiaLuv]

Well said Bron357.

On a side note - I looked at a vendor that had GIA Certs for pairs of rubies. One would think that the cert was for both stones. Nope just one, so, I guess you take a chance with the other stone.

 

[Bron357]

Well said Bron357.

On a side note - I looked at a vendor that had GIA Certs for pairs of rubies. One would think that the cert was for both stones. Nope just one, so, I guess you take a chance with the other stone.

Unless they are set into jewellery, where the usual approach is to “test” random gems, I would want a lab report for each ruby. Just because they are being sold as a pair doesn’t mean they are “the same”.
If the rubies are wee, then that’s not uncommon to test just one given the cost of a report & shipping vs the cost of the gem.

 

[demantoidz]

GRS explains the meaning of their 'H(a)' grading for insignificant residues:
'Extremely small residues of glass-like materials present in cavities or as isolated, extremely small residues in fissures that affect the weight of the gemstone less than approximately 0.001 carat.'

Gemstone Enhancement Disclosure -

Understand the different terminology for gemstone treatments and enhancements found in our GRS Reports

www.gemresearch.ch

 

[Autumn in New England]

Everyone, as usual, did a great job of explaining. As was mentioned, routine heat is considered a "standard treatment" for ruby, and is generally an accepted practice. Any type of fracture filling or lattice diffusion is considered "additional treatment" and is not generally an accepted practice (though tolerated by some if properly disclosed). So a filled ruby's value takes quite a dip over a traditional heated stone. I can't imagine all of the poor folks who get taken when they don't have a resource like PS. I'm not talking about you, OP, as you are obviously doing your research. But I think about jewelry store shoppers who likely won't receive or even know to ask for a lab report with a large purchase. eek

 

[DiaLuv]

Years back I bought a pair of round Burma rubies. Vendor cert listed heat treatment, nothing about residues or fillpings. At the same time I bought from same vendor an untreated Africa ruby. Vendor cert says unheated ruby. At the time I didn’t know I should get a certificate from a reputable lab. They are beautiful rubies but I sometimes wonder if I got ripped off.

I am much more cautious now about gem purchases thanks to PriceScope.

 

[Autumn in New England]

Years back I bought a pair of round Burma rubies. Vendor cert listed heat treatment, nothing about residues or fillpings. At the same time I bought from same vendor an untreated Africa ruby. Vendor cert says unheated ruby. At the time I didn’t know I should get a certificate from a reputable lab. They are beautiful rubies but I sometimes wonder if I got ripped off.

I am much more cautious now about gem purchases thanks to PriceScope.

Oh yes, we all have a learning curve as buyers (and sellers). Are you in the US, DiaLuv? If so, you could go ahead and send your rubies out to the GIA or AGL just to set your mind at ease. If you're located elsewhere, you have many other options as well.

 

[DiaLuv]

I live in Odessa Florida (Texas transplant). The rubies are set, but I just might send them to GIA in the future. I am waiting on my new ruby to come in and set it.

 

[Autumn in New England]

I live in Odessa Florida (Texas transplant). The rubies are set, but I just might send them to GIA in the future. I am waiting on my new ruby to come in and set it.

Sounds good! I believe both the GIA and AGL (for certain) will test mounted stones. Have you shared your new ruby on PS?

 

[DiaLuv]

Not yet. I waiting for vendor to send me a video of it first.