Hi Folks, We’ve had discussion recently regarding stones that are heat
sensitive and ultrasonic sensitive. I don’t ever recall any dialogue
about stones in pickle. Normally I wouldn’t do it, but found myself
backing up on a project to redo a hinge after I had already tube set a
green tourmaline. I guess one might also encounter this in a repair
situation… something I don’t often have to do.
I went through several books but didn’t find anywhere this was
discussed. (Note to self: check Alan Revere’s Ring Repair book). It’s
obvious to me porous stones and heat sensitive stones shouldn’t be put
into pickle. Diamonds and corundum stones are probably okay, huh? How
about tourmalines, topaz, amethyst/citrine, etc.?
By the way, my solution was to coat the stone and setting with
paraffin wax before putting in the pickle, although I was concerned
about the melting temperature of the wax being close to the pickle
temperature. I was right to be concerned - I pulled it out before the
acid got to the stone, but now I have bit of a greasy slick on the
surface of my pickle. Guess I should have gone with the dop wax…
which was my Plan B.
Make a list? No pickle for opals, emeralds, pearls,
turquoise/malachite/azurite family, rhodochrosite… If a stone is
heat tolerant can one also assume it will also be pickle tolerant?
Dave, I have put most inorganic gem materials, except for some things
like lapis, turquoise, azurmal in pickle without any reaction at all.
I have put emeralds in, too, although I won’t do that anymore on
account of the fillers being used today. Tourmaline should certainly
be ok, aqua, beryl, citrine, amethyst, as well. Opals I try not to
put in as well. Common sense should apply as always.
HI Dave, I have ruined peridot in the pickle. It gets an etched
surface instantly. I also do not allow pearl to come in contact with
it. I’m not sure about softer stones like turquoise or malachite but I
would say no. I’ve had no trouble with opals, tanzanite,amethyst,
emeralds though I would not leave them in for long. Patty Rios
I have immersed almost all stones in pickle for longer or shorter
periods with the major exception of the carbonates and a couple of
other stones. Pearl, mother of pearl, coral, all forms of shell and
bone have calcium carbonate as the major constituent. Other stones
that I have found affected a re lapis lazuli (also contains CaCO3),
turquise, doublets of all kinds, triplets of all kinds … Did I
leave some out?
Stones that are unaffected by pickle(sodium bisulfate): diamonds,
corundum, opal, emerald, tourmoline, topaz, spinel, tanzanite,
garnet, quartz, hmm… in fact, if they aren’t on the first list they
belong here. I ame careful with collector stones that I may not be
familiar with the properties. I also use my pickle cold and only
pickle as long as necessary.
Someone recently pointed out that pickle will affect some enamels. I
can attest to it. Be careful about soaking enamels in pickle.
Here’s are some little known facts about stones that shouldn’t be put
into pickle or subjected to certain processes jewelers use. Pickle
will etch the surface of peridot! And with the size and price of
some of those, that can run into money. So take care with those
mother’s rings, and while you’re at it, stong alkaline solutions can
be as damaging to some stones as pickle, as in if you are using a
high concentration of tri-sodium phosphate in your ultrasonic.
Peridot can be affected by that too. A lot of stones which normally
survive the caustic solution in pickle are nonetheless sensitive to
the heat that pickle pots commonly generate. Bi-colored tourmalines
can expand and crack along the color demarcation. Spectral Gems in
Birmingham Michigan used to give out a very nice little chart of how
different stones react to pickling, torches, ultrasonics, rude
setting techniques, etc. I’ll have to get a number for you tomorrow.
Saphire, although fairly resilient to torch work, can be etched by
boron containing flux, which is the case with most of the fluxes
jewelers use. And in the rare case of non-heat treated saphires
(which are expensive in good colors), they can contain minute pockets
(negative crystal growth) containing gases which can expand with
heating and cause fracturing in the stone. Watch out for the
"hmong-su" variety of rubies. Rubies generally withstand heating,
but this variety is often fracture filled with a material not much
better than glass. Heating these can provide some surprising
results. And for you trade guys out there that like to re-tip on
those worn out mother’s rings with synthetics (usually pretty safe if
you sneak up on them and don’t overdo it), you know that the old
green ones are really doublets, right? You wouldn’t heat them, but
I’ve seen them left in pickle and ultrasonics too long and a little
white line shows up around the girdle where the glue started to go.
The new green synthetics (used primarily in birthstone jewelry) don’t
fair too well under the torch either. Good thing they’re cheap.
They melt. . .must be akin to glass. What costs you here is not the
expensive of the replacement, it’s the lost time in re-setting,
usually involving new prongs too, at no charge, of course. LInde
Star saphires heat well, you can make them glow and they don’t go
away, but a genuine star saphire won’t take it. . . well, maybe, but
you’re pushing your luck. If I think of any other situations that
jewelers are often not aware of, I’ll post them. One more thing, you
can re-tip on a CZ, not small ones, but a bigger one, if you heat it
verrrry gradually, don’t overheat (use easy solder) and when you’re
done, lay it on a charcoal block you’ve heated up with your torch and
cover it with small metal container and let it cool gradually. I’ve
done it. You are justified in asking “but why?”. Let’s just call it
"research". Finally, never “quench” any stone. You can get away
with it with diamonds, but when you finally split one, you’ll have
paid dearly for the time previously saved.
Just another little aside on stones. Most blue and green diamonds
get their final shade of color as a result of iradiation. Putting
those stones to the torch can reverse that coloration process. Never
re-tip on a mounted blue or green diamond.