Heat treated or No Heat treating???

[woobug02]

I noticed that most of the sapphires at the Natural Sapphire company are not treated and most of the sapphires as AJS Gems are treated....What is the big difference and does it help or hurt the stone if it is treated... I am looking for a yellow sapphire (emerald or cushion cut )around 3.0 ct. Please give me details...

 

[chrono]

Call it personal preference. A very nice non heated sapphire is rarer and commands higher prices for bragging rights. Others have a budget and go for an equally nice (or usually better looking) heated sapphire.

In terms of heat affecting the stone, the colour is stable and the heated sapphire is equally tough. However, there is still some debate about how a heated sapphire will hold up after umpteen years compared to an unheated stone.

Most sapphires are naturally not very attractive unheated, so heating will make the colour richer and remove gray undertones, etc.

 

[woobug02]

Chrono, thank you sooooo much!!! Now I understand. What cut looks best in a yellow sapphire???? I have a clear RB one and it doesn''t do a whole lot for me.....It is untreated and pretty but kinda dull....

 

[chrono]

In coloured stones, cut does come into play, be it a round shape or cushion or whatever. If it is dull, it could be the cut and not the shape because round shapes is supposed to still be the most brilliant. Cut in gemstones is a bit harder to judge than in diamonds but with a bit of experience, you''ll be able to tell the difference. A badly cut stone will be dull, lifeless, might have a window, be lopsided, etc. You get the picture. My guess is that your sapphire is not well cut, but maybe the colour is good?

 

[Linda W]

Chrono,

I don''t think I agree with what you said about most unheated sapphires being unattractive because they are not heated.. My Padparadscha''s and the blue sapphire I purchased from The Natural Sapphire Company are to die for. Very deep rich colors. That is just my humble opinion though.

Linda

 

[strmrdr]

Date: 1/18/2008 10:47:36 PM
Author: Linda W
Chrono,

I don''t think I agree with what you said about most unheated sapphires being unattractive because they are not heated.. My Padparadscha''s and the blue sapphire I purchased from The Natural Sapphire Company are to die for. Very deep rich colors. That is just my humble opinion though.

Linda

You read it wrong :}
The majority of them are pretty fugly before heating and some after.
The ones that look great without heat are much more rare and that is why they are more expensive.

Personaly I like lightly heated for the value but dont go for filled and high temp heating.

 

[Linda W]

Thanks Storm,

Well, shame on me, I should have put my glasses on, while reading the post. Thank you Storm and sorry Chrono.

Linda

 

[strmrdr]

Date: 1/18/2008 11:17:04 PM
Author: Linda W
Thanks Storm,

Well, shame on me, I should have put my glasses on, while reading the post. Thank you Storm and sorry Chrono.

Linda

it happens too the best of us :} and you are one of the best people I know :}

 

[movie zombie]

heating is one thing....irradiation another. make sure just what the vendor means by the terms they are using.

movie zombie

 

[elmo]

Something else I think that''s pushed unheated prices up recently: an unheated stone will not have been subjected to most of the the more aggressive treatments like beryllium diffusion, filling, and fracture healing. So by selecting a natural unheated stone you''ve avoided a range of possible modern treatments. As more of these have come to light in recent years, it''s increased the demand for unheated stones.

 

[mugumbris]

Hi Woodbug
I do heat treating myself !which is a low temperature heat treatment.Heat treatment has been accepted in the industry for years but only a treatment that doesnt add any other material during the process.Now we have berylium heat treatment that adds a berylium flux to the process which changes the chemical makeup of the sapphire treated unlike normal heat treatment and is not accepted by the industry.
Since over 95% of sapphire on the market has been heat treated and the introduction of berylium heat treating,Untreated stones can bring a premium since it is straight from nature untouched and rarer.
If a stone doesnt need heat treating it isnt treated as simple as that,but not many stones have this quality in nature.
The shape of cut ,the type of cut(brilliant or step cut or mixed) and angles chosen for cutting all influence the final outcome of the stones brilliance and brightness.Also the polish and meeting of the facets.
So now I will show you my 2.85ct Trilliant cut sapphire from Queensland Australia.It's much more like canary yellow.
Mugumbris
P.s.It wont let me download photo and will post in another reply after this one.

 

[mugumbris]

here u go !!

 

[woobug02]

WOOOO thank you all so much!! I want a nice yellow sapphire... What cuts do you think work best in the yellow??? Like I said I have a really pretty clear untreated RB and it is very clean and clear but a little flat looking in certain lights.. I love the emerald and cushion cuts I found on AJSGems.... but sure about the cuts..

 

[mugumbris]

Hi
Personally I like a square emerald cut or a square cushion cut!Rounds are everywhere!!but you might like the shape of a round.They all work well with yellow.I think a stone of equal length and width works with yellow as it centralises or concentrates the colour to centre making it easier for the eye to absorb it if you know what I mean(hard to explain,sorry!!).
This gold sapphire might give you the idea of what I am talking about.
Regards
Mugumbris

 

[mugumbris]

Sorry Woobung I forgot to mention I am a commercial gem cutter(and teacher at the local technical institue TAFE) specialising in sapphire(15 years) on the NSW sapphire fields in Australia and Gemmologist.So if you want some more detailed advice on cuts please ask maybe I can help!
Mugumbris

 

[woobug02]

mugumbris... THANK YOU !!!! I am love the emerald cut What should I look for to make sure it will be a nice stone ????

 

[woobug02]

woo another question... What does lattice diffusion/heat treated mean???

 

[elmo]

Date: 1/21/2008 10:07:32 AM
Author: woobug02
What does lattice diffusion/heat treated mean???

http://www.gia.edu/library/4286/20426/faq_detail_page.cfm

In a way the high tech equivalent of dyeing the stone a different color. To me at least the treatment is so invasive that the stone may as well be synthetic.

 

[mugumbris]

Hi Woo
Diffusion lattice/heat treatment means that a poor quality sapphire,usually pale ,is heat treated with a flux that will put a thin coating of yellow over it suraface so changing its apearance from pale to a fine yellow.This treatment is not usually accepted i the Australian gem industry if its not diclosed to the customer.Remember the value of this stone is truly a small fraction of the real thing.
The reason the word lattice is used is that if the stone is observed closely you will see that the thin coating of yellow is in a pattern like bird wire(chicken wire similar to a Tennis net).This is an identifying feature.
Mugumbris

 

[mugumbris]

Hi Woo
In stone you should look for a nice a,rich appealing colour,a bright ,flashy ,brilliant appearance and no fish eyeing which means the stone is cut too shallow making it appear dead in the centre instead reflecting back at you.
Lastly,do you like it?do you like the colour,shape and size.
Mugumbris