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Mystery Rock


#1

Hello folks, I was up in the mountains of Prescott, AZ when I came
across some granite-like rocks with bands (about an inch wide) of
avocado-green. Do any of the minerologists out there know what the
green is? Can it be polished in to cabs or inlay? Thanks!

Sincerely,
JoAnna Kelleher, co-owner
Pearl Exotics Trading Company, LLC
Phoenix, AZ
Phn# 623.845.0998
Fax# 623.845.0917
www.pearlexotics.com


#2

JoAnna, I would recommend taking a piece to the Arizona Mining
Museum. Someone there should be able to tell you what it is and how
it’s been used in the past. I recommend checking out the museum
while your there. It is down by the State Capital 1502 W Washington,
PHX AZ 85007 602-255-3795.


#3

JoAnna

It is impossible to tell from such a short description but its
possible that the avocado-green may be hornblend. You need to chuck
off a small piece and test for specific gravity, scratch, acid,
fusion at least. Question, is there some jet black places in it? If
so that could make it more likely. Cheers from Don at The Charles
Belle Studio in SOFL where simple elegance IS fine jewelry.

@coralnut


#4

Hi JoAnna, You have EPIDOTE. There are several sites in the Prescott
area where these epidote veins also contain red piemontite. I tried
cutting some of this material (epidote in quartz) but would rather
spend my time working on other stones. Hope this helps. Will
Estavillo, Bisbee, Arizona.


#5

joanna if you want i could take a look at it and if i cant figure it
out i can take it to the geology dept. at my school. including
metals i am working on a geology degree with mineralogy being what i
am VERY interested in. if you do want to, you will have to get a
hand sample. about 4 x 4 piece and send it. what i will do is give
you a composition breakdown and whether it can be used for cut and
polishing and also if it reacts to any agents i.e. tarnish remover.
the reason why i say that is anything with calcium carbonate in it
desolves in tarnish remover. so let me know Maria Idaho State
University Fine Arts and Geology Majors


#6
    Hello folks, I was up in the mountains of Prescott, AZ when I
came across some granite-like rocks with bands (about an inch wide)
of avocado-green. Do any of the minerologists out there know what
the green is? Can it be polished in to cabs or inlay? Thanks! 

I wonder if this might be variscite (also known as Utahlite, found
in Utah). The only reference I could find of its occurrence was that
it is “formed by direct deposition from phosphate-bearing water that
has reacted with aluminium rich rocks in near-surface environments”.
Make of that what you will - perhaps some geologist out there can
tell us whether this is igneous (granite is igneous) rock business.

I have a small sample of this which is definately avocado green (the
colour of part you eat, not the skin that is). It has a hardness of 4
to 5 and polishes up to a waxy lustre and can look quite nice. Too
soft for a ring though.

Renate in Adelaide, South Australia where the rain is bucketing down
yet again and spring is hiding.