question on tourmaline and citrine

[Mag00]

Hello everyone,
I was wondering about citrine and certain colors of tourmaline.

I was reading that citrine is heated amathyst, and tourmaline, in certain colors, is aso heated.

my question is, is it natural heating? or is it heating it up unnaturally, in a lab or somewhere?

thanks

~Mag

 

[pyramid]

It is heated by man, I presume in a lab although I have read with sapphires that a lot used to be heated by man at the mines.

 

[Mag00]

Date: 6/16/2007 3:23:00 PM
Author: Pyramid
It is heated by man, I presume in a lab although I have read with sapphires that a lot used to be heated by man at the mines.

that is such a disappointment.

edit: isnt it possible for a natural one to occur?

 

[riogems]

Most of this type of heating occurs in an office, not in a "lab". I took some pictures of different ovens, and procedures... everyone has their own methodologies they follow. But generally, you set the temperature, the speed at which it gets up to that temperature, and the duration of the cook. There is nothing controversial about this -- it''s when they heat with the presence of other materials that diffuse into the stones and change their colors that it matters. Man has been cooking stones in oven-like apparatus for thousands of years. Most of the people at the mines don''t take any issue with this -- we typically cook most of our food too.

 

[pyramid]

Sorry MagOO I don''t know if Amethyst and Tourmaline come often unheated, I assume they do and would cost more, Sapphires cost a lot more when they are unheated. Maybe one of the professionals here could tell you.

 

[Mag00]

Date: 6/16/2007 3:48:05 PM
Author: riogems
There is nothing controversial about this -- it''s when they heat with the presence of other materials that diffuse into the stones and change their colors that it matters. Man has been cooking stones in oven-like apparatus for thousands of years.

thanks.

its not that its controversial, its more of a personal preference.
i tend to prefer gems that have not been altered in any way by man.

 

[twodoor2]

Heating is a common practice and generally accepted by the trade. It''s far less expensive to buy a ruby that is heat treated than one that looks the same, but is unheated. There are some other treatments that are far more controversial, like irradiation, beryllium treatment, coating, laser drilling (to remove inclusions in diamonds), and fracture filling. That''s why I refuse to buy emeralds, they are almost ALWAYS treated with fracture filling, and the type of filling can be colored plastic!! After hearing about some of the other horrid forms of adulteration of gemstones, heat treatment seems pretty tame. In fact most paraiba tourmaline that sells for thousands upon thousands of dollars per carat is heat treated. It''s worth far more heat treated than not, just like tanzanite (which when not heat treated looks like an ugly brown). With the case of paraiba, there is no guarantee that the untreated stone will turn out to the expected result after cooking, but if it does, megabucks!!

There is natually occurring citrine but it''s such an inexpensive gem that to buy heat treated or not really doesn''t matter that much. It''s when you talk about the big buck stones like rubies, emeralds, sapphires, and diamonds that you have to care more.

 

[Mag00]

Date: 6/16/2007 9:59:12 PM
Author: twodoor2
Heating is a common practice and generally accepted by the trade. It's far less expensive to buy a ruby that is heat treated than one that looks the same, but is unheated. There are some other treatments that are far more controversial, like irradiation, beryllium treatment, coating, laser drilling (to remove inclusions in diamonds), and fracture filling. That's why I refuse to buy emeralds, they are almost ALWAYS treated with fracture filling, and the type of filling can be colored plastic!! After hearing about some of the other horrid forms of adulteration of gemstones, heat treatment seems pretty tame. In fact most paraiba tourmaline that sells for thousands upon thousands of dollars per carat is heat treated. It's worth far more heat treated than not, just like tanzanite (which when not heat treated looks like an ugly brown). With the case of paraiba, there is no guarantee that the untreated stone will turn out to the expected result after cooking, but if it does, megabucks!!


There is natually occurring citrine but it's such an inexpensive gem that to buy heat treated or not really doesn't matter that much. It's when you talk about the big buck stones like rubies, emeralds, sapphires, and diamonds that you have to care more.

ah ok, thank you

this is why I dont like blue topaz's - they're irradiated

anyways, thanks for the info.

can Amethyst be treated? ive seen some VERY purple specimens, and I always wonder if its natural, like if its from the very tip of the stone (like in the geodes the tips are darker than the base), or if its been treated somehow

 

[twodoor2]

I don''t think amethyst can be treated, but the thing to be super careful with amethyst is that there is a lot of synthetic (lab created) amethyst being marketed as natural. You have to be very very careful since it looks very similar to the real thing, and only buy from reputable dealers.