Untreated Blue Sapphire (articles on durability, rarity relative to treated stones

[winky42]

Could anyone direct me to publicly available articles on untreated BLUE sapphires that address the durability/rarity issue? I''d like a reputable scientific source indicating that treated stones are fundamentally different (more fragile, incompletely colored, more prone to breakage, etc.)

Thanx!
SC

 

[Teresa]

Hi Winky 42,

I've listed a site that I found very helpful regarding heated vs. unheated sapphires. Hope it helps you. I cannot say what this site says is true, though. Make up your own mind.

http://www.sapphires.ca/index.html

 

[mogok]

Well on the rarity/durability issue, I dont think that you will find a lot of things on internet.
You can go to see some laboratory websites... But they are scarce in information.

There is www.ruby-sapphire.com from Richard Hugues, with a lot of interesting articles. Richard is a well known authority on Burma, Ruby and Sapphire. He is very involve in the beryllium controversy and webmaster for palagems.com. He is not really a scientific but a gemologist.

There is www.themelis.com from Ted Themelis. Ted is a specialist on burma and on heat treatment. He is also very involved in the beryllium controversy. Ted is not a gemologist he is a traveller, writter and heat treatment expert.


Then you can visit other sources from laboratories, like www.gemresearch.com from Doctor Peretti can give you also some informations... Doctor Peretti is a real scientist with several diploma in chemistry, geology,...

By crossing these 3 persons that are not really the best friends in the world, but that are all very good experts in this domain, I'm sure you will be able to get some very correct information.
There are several other website that might give you some infos, but not that much.

Now if you just want my opinion on the subject, here is what I can tell you:
The point is that natural unheated ruby or sapphire can be less durable if they present some fissures than a heat treated stone for which the fissures were closed using some flux.
Now a stone that was heat treated is usually not less durable than a stone that was not except if the heat treatment has created some fissure around some inclusions that could make the stone break in case of a blow... If a ruby or a sapphire is correctly heated, present no fracture, then we can say that the durability is the same.
Now on the rarity issue it is clear that a unheated fine color fine clarity ruby or sapphire is much more rare than a heated stone of equivalent color and clarity. the purpose of heast treatment for ruby and sapphire in to enhance the color and the clarity of the stone. Some people are really doing very well with that and many fine stone leave their heat treatment furnaces...

All the best.

 

[valeria101]

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On 6/21/2004 4:38:35 AM winky42 wrote:



I'd like a reputable scientific source indicating that treated stones are fundamentally different (more fragile, incompletely colored, more prone to breakage, etc.)

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Actually, I do not think there is such evidence - or the issue itself

I was about to make a long post, but Mogok just said in two words (plus the appropriate amount of authority) that the durability Q is blurred - heating both cures some ills and opens others. Heating does reduce color zoning and definitely improves appearance - not much to say against that. However, you will find a range of arguments in favor of the stronger valuation of natural sapphire: most revolve around two facts - the more reliable identification of absence of treatment as opposed to making a difference between traditional and more invasive treatments (such as high temperature heating and diffusion, which are regarded as undesirable) and rarity.

As far as I know, these two arguments work somewhat like this:

The most evident difference between treated and untreated sapphire seems to be on their market, not structure. You may find retail reports such as (THIS and THIS interesting.

The foundation of this should be rarity, I think, more than anything else. You may find notes on the history of (progressively radical) treatments useful to making an argument about color and rarity as pricing factors. One such article and sources are HERE.

Another qualitative argument for the value of untreated sapphire relates the value of the treated material with that of the original that underwent treatment (along the line that the more "value added" comes from treatment, the less favorable the comparison with untreated material). For example...this.

The topic has a huge following, so details about what treatments do can be found published by each and every of the major gem grading labs... all had recent updates on sapphire treatments, and post articles online. PalaGems.com lists quite a few among their "News" and the inherent list of sources is a good start too. Same about the "Links" on Ruby-Sapphire.com

Happy hunting !