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Treating temperatures for Zoisite


#1

Can anyone tell me what the heat treating temperatures are for
Zoisite. I understand the process presents some amazing results.

Thank you for your time and consideration.

Sincerely,Tom Miller


#2

If you are referring to the the temperature necessary for producing
the blue color in zoisite, check:

http://www.galleryvoltaire.com/tanzanite.html

Hope this helps.


#3

A couple of years ago, I treated about a kilo of brownish tanzanite
rough. I put the gravel in a beaker and heated it to 900 to 1000
degrees Fahrenheit over a 3-4 hour period in my burnout oven. I
turned the oven off and let all cool overnight. This was small
stuff, up to but not over 1ct stones. All went well.

A little surprise was that some of the pebbles about 1/10 of a
percent turned an emerald green.

Bruce


#4
    Can anyone tell me what the heat treating temperatures are for
Zoisite. I understand the process presents some amazing results. 

Tom, if you mean the brown, transparent type of zoisite that is
heated to make it into blue tanzanite, it is generally heated to
1100F to 1200F (600C to 650C) to get that rich, velvety
violetish-blue. Some of the transparent green zoisite is also heated
in that range. This is they type of zoisite that grows in a crystal
structure, not the aggregate.

If, however, you mean the green aggregate type of zoisite like the
"ruby in zoisite", I have never heard of heat treating it for any
reason.

James in SoFl


#5

You can get blue “ruby in zoisite,” so maybe that’s been treated. I
have some blue beads and they’re not very attractive, I can tell you
that.

Courtney
Courtney Graham Hipp
cgHipp Jewelry Designs