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Problem with sapphires


#1

we have had 2 sapphires in the last 3 years go south on us. one was
a very pretty celon blue in color, our cost, was over $3000.00.
was in a ring, was sized with out protection to stone, hey its a
sapphire. was air cooled to where you could place your finger on
stone, but still warm and dunked in citric acid, and the sapphire
came out looking like a quenched cz?? internal cracks galore.
needless to say the boss was not happy, fast forward a cpl years.
this is a dark blue large sapphire clear. was in a pair of
earrings, surrounded by diamonds in a basket mounting. cut the
mounting apart to put into ring for customer and the heat involved
here was not as direct as tipping, soldering a heat to a mounting
kind of heat. this stone was not quenched, was air cooled and it
looked like a crazed cz just as first one did.

are these stones treated?? any would be very helpful, as
of now any expensive stones are being treated like a emerald, no
heat

thanks
ringdoc


#2

I have commented on this before and I will say it again. I don’t
believe any colored stones should be subject to heating anymore.
There are too many unknowns in the way they are treated (and the
treatments are changing so rapidly) so that it is impossible to know
exactly what you are dealing with anymore. My advice is to always
remove the stones and if that is not possible than protect them in
something like Kool-Jool.

Daniel R. Spirer, G.G.
Spirer Somes Jewelers
1794 Massachusetts Ave.
Cambridge, MA 02140
617-491-6000
@spirersomes
www.spirersomes.com


#3

Ringdoc,

Interesting issue. In the old days, so I’m told, jewelers regularly
heated sapphire with no ill effects. Have done this myself with no
ill effects. Today with 95% of stones heat enhanced there seems to be
a weakness in the resulting gem. Heat enhancement is carried out at
extremely high heat, often close to the melting point of corundum.
Some have said that the resulting stone has a more brittle character.
Others have said that the heating actually anneals the stone
eliminating natural internal stress.

Your experience seems to support the former theory. Our smiths are
reluctant to work around a set sapphire. Seems like caution is
advised here.

Richard


#4

I would have asked the retail client to allow you to remove the
expensive stone prior to heating the stone. have ‘that’ person sign a
"release of your responsibility" to any damages that might occur.
this method might save your self-steem and bank account! better safe
than sorry! I suggest the high heat travelled up to the stone through
the gold being soldered. Borax coverings would have solved some of
the “high heat” problems Gerry!


#5

I tend to agree with you richard, I have taken sapphires to a dull
to med red before and let em cool a bit and quench in pickle, but no
more, I will treat em like a emerald in all future heatings. thanks
for the comments from all, would still like a good reliable reason
as to why. ringdoc


#6

All, Borax coverings would have solved some of the "high heat"
problems .

Please do not cover your corundums (ruby/sapphire) with borax.
Peter Rowe gave a very good explaination several months ago regarding
the potential of burning these gems when covered with borax. Check
the archives!!

Cheers from Don at The Charles Belle Studio in SOFL where simple
elegance IS fine jewelry! @coralnut2