At 10:45 PM 10/30/96 -0600, you wrote:
Dave Stephens wrote:
PS, someone mentioned stones that are solderable? Would that be jade
(nephrite?) and what others are safe? Dave
Diamond is one and there is a list of the heat tolerance of various
stones in GIA but don’t have a copy of it handy perhaps
someone else has it. You might check other texts for such a list
I am a Lapidary and have done extensive testing on heat treatment of
Gemstones.I don’t know how you’d get a stone to stick to anything,but
Sappire and Zircon can take well over 1,000 C and Tourmaline(clean that
700-750C,goes white and clouds at 800.Your Quartzes can go 500C then at
higher temp opalize.Beryls same temperature,over 500C go white and
cloud.Garnets are uneffected by the highest temperatures.Topaz will white
out at 200C.But will stay clear as high as you go.
This regards temperatures up to 1,000C.Seems to me,if you could tack the
stones into the setting,it would be a lot quicker and easier,but would’nt
the solder reflect inside the stone?And also,you’d probably scorch and
smear a film over the facets,so they would have to be repolished.Polishing
a stone in a mounting is difficult,but do-able on the crown,but the
Not to mention what you’d do to coloration of stones with all that heat.
You’d induce color changes,even if the stone stayed intact.Or destroy color,
all irradiation induced color change reverts at max 500F.
I think some lady is going to punch you in the nose when she gives you a
nice dark Amethyst and you hand her back a Citrine.You gonna make my Green
Beryl-Blue.I’m going to bring you the finest Gem Indicolite and you return
to me Green.
Did not even discuss all the stones you are going to crackle.Even at
what I called safe temperatures you are at great risk heating a
stone.Stones have like pores,like in your skin.and these pores can be
filled with microscopic liquid.
You’ve seen the moving water bubbles in Quartz,etc.That’s the same thing on
a grand scale.Crystals can grow,stop,then grow again,leaving space.This
space expands and contracts on heating.Bang!you’ve crackled Mrs Big Bucks’s
stone.Now your for it.
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