Setting rough stone

Hello

I’m a metals student at Bridgewater state college in Massachusetts
(about an hour south of Boston). I’ve concentrated my work to jewelry
and I’ve come to find that I need certain stones that Rio and the
likes can’t provide. I bought a piece of garnet called andradite and
I’d like to set it into a ring. I could only find it in its raw
crystal form however.

I’m wondering what to begin with to get this to the point where I
can set it. I’m not looking to facet this myself or anything, I’m
merely looking to cut off a piece of the crystal to use in place of a
traditionally cut and polished stone.

Thanks,
Patrick

I bought a piece of garnet called andradite and I'd like to set it
into a ring. I could only find it in its raw crystal form however.
I'm wondering what to begin with to get this to the point where I
can set it. I'm not looking to facet this myself or anything, I'm
merely looking to cut off a piece of the crystal to use in place
of a traditionally cut and polished stone.

I’ve set black andradite in a bezel setting. I started by selecting a
piece that had nicely formed crystals on a relatively flat plane.
Then using a flat lap ground the host rock into a flat base. Keep
grinding until you are down to just enough of the host rock to be
covered by the bezel. I used 3/16 bezel for the setting. Once you
have enough host rock ground off shape the sides of the stone. I did
a free form shape and let the stone dictate the size and shape. Once
you have it shape grind a slight bevel inwards so that you can set
it and snug the bezel to hold it. I used cryogenic glue (super glue)
when setting the stone. You may lose a few crystals during the
process so start with a larger piece.

Rick Copeland
Silversmith and Lapidary Artisan
Colorado Springs, Colorado
rockymountainwonders.com

I bought a piece of garnet called andradite and I'd like to set it
into a ring. I could only find it in its raw crystal form however. 

You may need to identify it further before working with it. Andradite
is one of the 6 main species comprising garnet group. Others aRe:
spessartine, pyrop, almandine, uvarovite, and grossular. Adradite
have 2 important varieties demantoid and topazolite. It is well worse
an extra effort to identify whether or not you have crystal which may
have a potential of becoming a gem, since both varieties are rare and
expensive if specimens are of high quality.

Leonid Surpin.

Patrick - you should have some local rock clubs up your way. Check
out the American Federation of Mineralogical Societies site -
www.amfed.org - for a club near you. They probably give workshops on
stone cutting, and if not probably have a member who could help you
cut the stone the way you want it.

Best wishes.
Beth in SC

Your first priority should be the mechanical aspects of it. Is the
stone suited as is to being held in some manner? Can you saw it in
half perhaps and get two sorta like pseudo cabochons? having a flat
back will go a long way in suggesting how to hold it. Get a good
bearing and the rest isn’t so hard. Prongs or bezel, depends on the
shape of things. Or a combination of the two.

How well formed is the crystal? Can you use that to your advantage?

Sawing isn’t as big a job as it sounds. A diamond wheel in the
flexshaft could do it if you’re careful to avoid heat buildup and
chattering.

maybe you could drill thru it and use a wire to hold the thingie in
place. Ballup the ends or make it a screw. I once used a 4 ct diamond
in a bezel mounted on a screw to hold an onyx saddle ring together.

Grind a groove around the largest circumference and use that as your
bearing surface, like the old scarab bracelets kinda, but double
sided

Ok my head hurts now from thinking.