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Author:  Cinnabar [ Wed Dec 14, 2005 4:08 pm ]
Post subject:  Prasiotrine?

Here's something to throw out there...

Is it possible to create via heat treatment a bi-colored prasiolite/citrine stone?

I wandered into this thought through the ametrine doorway... If most citrines are heated amethyst, and ametrine can be replicated by sticking half a stone in sand and heating it up ... then it seems like the theory might fly. Any thoughts, predictions, guesses?

Author:  JB [ Wed Dec 14, 2005 4:34 pm ]
Post subject: 

That's an interesting question Cinnabar. One that might require a chemistry major to answer. But off the top of my head I would say that the different heating enviornments such as temperature, length of time heating and cool down period required for the resultant color's, along with thermal inertia may preclude those exact results.

Don't really know, just shooting arrows in the air and hope they hit something close.

Let's see, green and gold. Are you a Notre Dame fan?

Author:  Gem├ža [ Thu Dec 15, 2005 5:47 am ]
Post subject: 

Dear Cinnabar.

what I have read and understood (I have may be some missunderstanding :? ) on prasiolite is:

-Prasiolite (leek green quartz) come from heating amethyst or fumed quartz from specific locality (Brasil, California, Arizona, Zimbabwe ).
-Citrine come from heating Amethyst.
-If you heat (again) prasiolite, it possibly come colourless.

I think (just a suposition ) this si difficult to have prasiolit-citrine by heating.. :P
May be prasiolite-colourless quartz ?

More pragmatically: I have never see this type of mixed colors (prasio-ctrin) in mineral show (like sainte marie aux mines in France) ... :roll:

What I am sure is the Hight complexity of changing color in quartz by heat.
The change of color is a fonction of:
Temperature, Heating time, Trace elements in the quartz and their concentrations, Cristal orientation, etc.
Fe3+ in citrine, Fe2+ in prasiolite, Ti in rose quartz, color center with Al in fumed and morion quartz, Color center with Fe2+ or Fe3+ for amethyst color....
I have a publication (pdf file in french) on the possible change with temperature and/or irradition... Every time I read this publi I beat my head on my desk.. :D

If you read french (and have a solid head) I can send you this publi :wink:

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