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What gems take heat? (was MACS and Hinges)


#1

Not to the best of my knowledge. The only stones which I believe to
take heat are diamond, ruby, and sapphire. I have however, found that
some lab created emeralds will take heat. THIS IS A GREAT IDEA FOR A
THREAD! WHO ELSE HEATS ON WHAT STONE?

Hmm, things that can take heat include diamond, corundum (as above), some
garnets (about 1 in 50 pyropes anyway turn to a black lump, many
survive-personal observation). Synthetic courundum and synthetic spinells
will take heat with no problems-just don’t quench anything you’ve heated
up. You can cast with them too. The issue with some stones is inclusions,
even in ruby and saphire-be careful when heating things. You are not
supposed to put flux on corundum surfaces at high tempertures, it can etch
them.
I’ve also heard that diamonds get cumulative damage with time, that after
about 20 minutes worth of heating at soldering temperatures they start to
’burn’. You can also ‘burn’ them at too high a temperature. Can anyone
corroborate this?

Charles

Brain Press
Box 1624, Ste M
Calgary, Alberta, T2P 2L7
Canada

tel: 403-263-3955
fax: 403-283-9053
Email: @Charles_Lewton-Brain


#2

from what i understand and have experienced a diamond will scorch if
heated TO HOT, i also understand that this is only surface and can be
polished clean again . keep on truckin’


#3

At 08:13 PM 11/3/96 -0600, Charles Lewton-Brain wrote:

Hmm, things that can take heat include diamond, corundum (as above), some
garnets (about 1 in 50 pyropes anyway turn to a black lump, many
survive-personal observation). Synthetic courundum and synthetic spinells
will take heat with no problems-just don’t quench anything you’ve heated
up. You can cast with them too. The issue with some stones is inclusions,
even in ruby and saphire-be careful when heating things. You are not
supposed to put flux on corundum surfaces at high tempertures, it can etch
them.
I’ve also heard that diamonds get cumulative damage with time, that after
about 20 minutes worth of heating at soldering temperatures they start to
’burn’. You can also ‘burn’ them at too high a temperature. Can anyone
corroborate this?

Well, I just turned in for polishing about 5-6 carat in mellee diamonds that
I have “runt” over the last decade and a half. About half of which were
burned. Most were burned while working too close in platinum.
Lately, I’ve been experimenting with casting gold with diamonds already set.
Mellee only at this point. I don’t think I’ll ever try on carat sized goods.
Seems that they will withstand heat of under 900 degrees F. If memory serves
me correctly, the GIA some years ago determined that they were safe at up to
875F. These temperatures have proven sufficient to get pretty good castings
lately. One precaution. I’ve tested this and it is important. Don’t allow
diamonds to touch each other (as in a channel setting) when casting with the
stones in place. Intuitively, it would seem that when placing two immovable,
and unforgiving objects against each other that thermal changes might bring
about some change in their physical appearance. It is a big mistake. Maybe
it is ok if you don’t quench it. I doubt it. I let the casting cool off
considerable before I quenched it. I think that there is just plain too much
tension.
It is late. I punched this out in a hurry. Hope it is somewhat readable.

E-mail: manmountaindense@knight-hub.com
WWW: http://www.knight-hub.com/manmtndense/bhh3.htm
Snail: POB 7972, McLean, VA 22106


#4

On the subject of diamonds burning up… Absolutly… Although I personally
have never been as unfortunate to actually do it, I have seen the results of
this… I personally think it is VERY hard to actually burn a diamond. However
a person I now work with burned up a few 5 pt. diamonds when she got in over
her head on a platinum job she had no business working on… (due to much lack
of experience) Anyway she was tipping some prongs on a platinum peice prior to
me working at this particular store, and she actually used platinum to tip the
prongs with the stones in place… BIG MISTAKE… They may be the hardest stone
and they due take alot of abuse but they WIL burn with that much heat…My
advise on platinum tipping… tkae the stones out (all of them) and proceed or
tip them with 18 kt white gold solder…
Other stones that take heat include rubies and saphires, however many
saphires are treated and may lose color. This is from experience… I have
never had a problem with rubies…
MarcFrom: owner-orchid@proteus.imagiware.com on behalf of Charles Lewton-Brain
Sent: Sunday, November 03, 1996 9:13 PM
To: orchid@ganoksin.com
Subject: What gems take heat? (was MACS and Hinges)

Not to the best of my knowledge. The only stones which I believe to
take heat are diamond, ruby, and sapphire. I have however, found that
some lab created emeralds will take heat. THIS IS A GREAT IDEA FOR A
THREAD! WHO ELSE HEATS ON WHAT STONE?

Hmm, things that can take heat include diamond, corundum (as above), some
garnets (about 1 in 50 pyropes anyway turn to a black lump, many
survive-personal observation). Synthetic courundum and synthetic spinells
will take heat with no problems-just don’t quench anything you’ve heated
up. You can cast with them too. The issue with some stones is inclusions,
even in ruby and saphire-be careful when heating things. You are not
supposed to put flux on corundum surfaces at high tempertures, it can etch
them.
I’ve also heard that diamonds get cumulative damage with time, that after
about 20 minutes worth of heating at soldering temperatures they start to
’burn’. You can also ‘burn’ them at too high a temperature. Can anyone
corroborate this?

Charles

Brain Press
Box 1624, Ste M
Calgary, Alberta, T2P 2L7
Canada

tel: 403-263-3955
fax: 403-283-9053
Email: brainnet@cadvision.com

procedures


#5

I’ve also heard that diamonds get cumulative damage with time, that after
about 20 minutes worth of heating at soldering temperatures they start to
’burn’. You can also ‘burn’ them at too high a temperature. Can anyone
corroborate this?

As long as you keep oxygen away from diamonds they won’t burn. I heated
diamonds to a glowing red heat with no damage (with a heavy boric acid
covering). Burning a diamond first turns the surface chalky white, then
the body of the diamond starts turning blue after prolonged heating at
high temperatures.

A friend of mine works at the SLAC (Stanford Linear Accelerator Center).
They use thin slices of chemically pure diamond to align the electron
beam. After a few days use the diamonds become unusable because of
damage to the cubic matrix. They also turn blue at that point.

A possibly interesting point, he explained to me that the distance
between the carbon atoms in a perfect cubic matrix (atoms at the corners
of a cube, each cube adjoining the next…) is the same as the
wavelength of blue light. Therefore, chemically pure diamonds (better
than true D-flawless) exhibit a blue-white color, thus the old and
obsolete term of “blue-white”. The public never sees diamonds of this
purity, they are used in science research however.

         Jeffrey Everett

Handmade 18K, 22K, and platinum gemstone fine jewelry.
Diamond setting, rubber/metal molds, casting, lapidary
Die and mold engraving, plastic patterns for casting.
Cad jewelry design, cad/cam milling scroll filigree…
P O Box 2057 Fairfield IA 52556 515-469-6250


#6

I can attest to this. About 10 years ago I cast an eternity band
composed of .25 ct. baguettes. They were all touching! None burned, but
two came out fractured. Gold puts A LOT of pressure on the diamonds when
it shrinks as it cools!!!

One precaution. I’ve tested this and it is important. Don’t allow

diamonds to touch each other (as in a channel setting) when casting with the
stones in place. Intuitively, it would seem that when placing two immovable,
and unforgiving objects against each other that thermal changes might bring
about some change in their physical appearance. It is a big mistake.

         Jeffrey Everett

Handmade 18K, 22K, and platinum gemstone fine jewelry.
Diamond setting, rubber/metal molds, casting, lapidary
Die and mold engraving, plastic patterns for casting.
Cad jewelry design, cad/cam milling scroll filigree…
P O Box 2057 Fairfield IA 52556 515-469-6250