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Heat treating amethyst


#1

The locality in Brazil for the amethyst is unknown. I checked
for brown color zoning, there is none. The colors of colorzoning
is just lavendar and colorless. If I heat treated this material
do I have to get it faceted first or would you recommend heat
treating in the rough form.

Surbhi


#2

The cleaner it is the less likely you will have breakage.Even a
small surface tick can spread with heat and split the stone.Best
to take it at least into a sanded preform,But you can heat
rough.If you want to just do it a lot more slowly to reduce the
chance of breakage.For example,the Amethyst,placed in a crucible
with sand,you could take directly up to 450C,hold 2 hours or so
and let cool.If you want to insure better recovery from
breakage.First heat the stone in a toaster oven to 500F.Let
cool.This helps to stabilize it for the higher temperatures.Then
do that same cook to 450C,but do it over 2 days.Start at 100C and
raise it every hour or two just a little until you reach the
450C. Your zoned piece may come back as 2 colors of Citrine.A
real pro when doing bulk heat treating of Maramba or Brezeina
Amethyst will saw off the brown streak,knowing this will give
dark Citrine.And saving the side that will be light Citrine as
the original Amethyst.Logic being the Amethyst will bring more
money than the light Citrine. Actually it is encourging that your
piece is zoned.Remember Amethyst fades with long exposure to
sunlight.If you piece was found on the surface or sat in your
window it has faded from the original darker colors.What you may
see as white and light lavendar may have been brown and dark
Purple.Lastly,if you open your oven door,and see an all white
stone.It may not be overdone.heat it again to 475C or even 500C.
But over 500 Quartz will go permentaly white.In fact it can do
what I call “Opalize” It comes out all milkey and with some play
of color.Looks just like an Opal.In Brazil they will try to sell
this overheated Amethyst for Opal to the unwary. If you are
looking for good Citrine cooking rough,I am about to buy 5,000
kilos of Old Maramba,browish rough.2-3 months before it gets
here buy boat,but the best Citrine will come out.

                                           Mark Liccini   
     LICCINI

Gemstone Rough Dealers since 1970 U.S.MAIL
E-Mail: @Mark_Liccini1 107 C.Columbus Dr.#1A
http://www.LICCINI.com Jersey City,N.J.07302
Voice Mail/Fax: 201-333-6332