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Soldering colored stones


#1

Hi,

I need to change a post on a 14K gold yellow sapphire that is
bezel set. I have a few questions:

1.  Is this possible?
2.  If so, what precautions should I take?

Any help would be appreciated, of course this is due
tomorrow…

Thank you in advance.

Linda Crawford
Linda Crawford Designs


#2

Linda, We always feel that due to the large number of treated
stones on the market that it is always safer to remove all stones
from their settings before soldering.


#3

Linda:

Two things, how big is the stone and is there much distance
between it and the soldering area? I have had no trouble
soldering around smaller blue saphires however, the larger ones
can be treated and could be expensive to replace. If you have
some space to work in, you might get lucky with a cooing jell.
If possible, remove it just to be safe. Factor your labor and
any costs to repair the stone if you should damage it during
removal. If they should find the cost too high, let them take it
down the road.

Good luck;

Steve


#4

Dear Linda, genuine sapphires and synthetic sapphires will go
through the fire without any problems providing they’re not too
heavily included. Some inclusions have a different coefficient of
expansion to the surrounding material and this could cause
fracturing. If the sapphire is free from inclusions (a little
"silk" in the stone won’t matter) just make sure that the stone
is clean, no fingerprints or dirt left on the stone, and be
careful not to let any flux burn onto the stone while you are
soldering. Some fluxes will etch into the surface when heated.

Your mention of a yellow sapphire sounded an alarm bell which
began with my own experience some twenty years ago. I had a
parcel of what I thought were beautiful golden-orange sapphires.
We used some in a ring which had to be resized and blithely went
ahead just as we always had done, doing the resize with the
stones in place.

As the ring was heated, all but one of the sapphires went
transparent white. So did our faces! We immediately took action
against the Australian dealer who was as horrified as we were.
The matter was eventually traced back to a Sri Lankan dealer
whose brother was a radiology technician. They had been dosing
white sapphire with heavy X-ray bombardment to turn them a
beautiful deep (and highly expensive) gold colour. Trace
elements in the white sapphire respond to X-ray irradiation. It
only took a little heat to dispel the colour - about boiling
water hot.

I’m very careful with golden sapphire if the provenance is
uncertain, and insist on warm-testing such material before
buying. I don’t want to frighten you, but it happened to me,
so… Hope this helps, Rex from Oz


#5

Hi, First of all I want to thank everyone for the valuable input.
As it turned out I decided to take the stone out of the setting
and complete the repairs. To answer Steve’s questions the
distance between the stone and the soldering area is an estimated
1mm. The stone itself is a 6mm stone. I am not sure of the
background of the stone…the customer supplied the stone which
a friend of his purchased at a gem show…when, where and
who…? Since, the stability of the stone was at question I
took the conservative approach (cluck, cluck). The setting
turned out excellent.