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Garnet Heat Sensitivity


#1

Hello all A few months back, I posted a comment about garnets being
very heat sensitive. Well, I now think that comment was based more
on “conventional wisdom” rather than fact. I have been faceting
Demantoid garnets for the last month or so and I can tell you that
the way I have treated these stones with the alcohol lamp is in
contrast to my prior beliefs about garnet. I am doping with brown
wax and placing the garnet directly in the flame while position it.
After transfer with epoxy, I remove the stone from the dop using the
alcohol lamp again, getting the stone so hot that I need a towel to
hold the stone. I have yet to have a problem with these stones.
This is based on the experience of cutting over 30 of these stones
in the last month and a half. I am not sure I want to place a torch
on a tip just yet, but who knows, a little more experimenting might
change my mind about that also.

Don


#2

Don, indeed garnet will stand up to an alcohol lamp when dopping but
would not suggest hitting one with a torch flame. Suspect you will
end up with many small garnets. Garnets, as you most likely know,
are of the silicate group which can be sensitive to heat. Garnets
fusibility ranges from 3 to 6 but the iron found in most and loose
crystal structure makes them subject to fracture.

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry. @coralnut1


#3

Don, Alcohol lamps and torches vary quite a bit as far as heat goes.
I would not subject the garnet to the direct heat of the torch for
very long if at all. I have tried it and it fries the garnet although
I have sized many garnet rings and subjected them to heat I always
put them on the mandrel as soon as the solder flows and do not
subject the stones to direct heat.

Regards J Morley Coyote Ridge Studio


#4

Hi Don,

  A few months back, I posted a comment about garnets being very
heat sensitive. Well, I now think that comment was based more on
"conventional wisdom" rather than fact 

I haven’t tried all varieties of garnet, but I’ve used some 4 mm red
(pyrope?) beads from India in a sterling bracelet. The design of the
bracelet required soldering (medium sterling) right next to the bead
. Generally the beads took the heat with no problems. An occassional
bead would break, but that could have been due to an inclusion or
defective bead.

Dave