Back to Ganoksin | FAQ | Contact

Frosting of peridots


#1

Hi everyone, I am working on a pair of 22k earring set with faceted
peridots. I put them into my pickle pot for a few minutes after I
had set the stones to give them a brighter gold color and when I took
them out the stones appeared to be dul l and had lost their sparkle.
Has this happened to anyone else? Can anything be done to fix this
disaster?

Thanks for any help. By the way I always enjoy reading everyone’s
postings and have learned much.

Mark Sann
msan40@aol.com


#2
   Hi everyone, I am working on a pair of 22k earring set with
faceted peridots. I put them into my pickle pot for a few minutes
after I had set the stones to give them a brighter gold color and
when I took them out the stones appeared to be dul l and had lost
their sparkle. Has this happened to anyone else? Can anything be
done to fix this disaster? 

Peridot happens to be attacked, though slowly, by pickling acids. A
brief dip to remove flux or very light oxidation is usually OK, but
longer than that, and it gets frosted. The pickles made with actual
acid attack peridot more quickly than do products like Sparex, but
even they will attack it. About the only fix is to repolish the
stone. If the frosting is very slight, you can use an ordinary buff
or brush in your flex shaft with some cerium oxide lapidary polish,
or fine grit (14000 or higher) diamond compound, or even platinum
rouge (the white, 8000 grade compound from gesswein is especially
effective) to brighten the surfaces again, but this type of buffing
on a facetted stone will round over facet edges, so the stone isn’t as
’crisp" any more. remember too that you have to do the pavilion as
well, if the result is to look good, and this may be difficult in
many settings.

Peter


#3

Yep! Happened to me too. I suppose you could have them repolished
but given the low value of peridot it may not be worth it. Jerry in
Kodiak


#4

PERIDOT

Heat    				-    avoid high heat or sudden changes
ACIDS    				-    avoid
SOLVENTS    			-    avoid
SOAP    				-    ok
STEAM    				-    avoid
ULTRASONIC    		-    avoid
POLISHING AGENTS    -    avoid

Jeweler’s Resource revised edition Bruce Kunth

It would probably be cheaper to replace them rather than re
polishing them.

ROBB - Retired Old Baby Boomer


#5

According to Jon Sinkankas’ “Gemstone & Mineral Data Book”, peridot
is attacked by warm sulphuric acid, and is best not treated with any
acids whatsoever. Seeing as pickle is basicly sulphuric acid, pickle
and peridot make for a bad combo. Probably the only thing that can
be done to the stones is to recut or maybe repolish them.

Richard, in chilly Michigan (and wanting it to get colder)


#6
Hi everyone, I am working on a pair of 22k earring set with
faceted peridots. I put them into my pickle pot for a few minutes
after I had set the stones to give them a brighter gold color and
when I took them out the stones appeared to be dul l and had lost
their sparkle. Has this happened to anyone else? Can anything be
done to fix this disaster?" 

Hi Mark, Sorry to be the bearer of bad news, but not only has this
happened to some folks, it’s happened to everyone, at one time, or
another… welcome to the gang! What you did, when you put those
Peridots in acid, was to begin to dissolve them. Peridots,
Diopsides, Enstatites, Epidotes and the calcium-based Grossular
Garnets are all susceptible to fresh acid pickles, to one degree or
another, just as lime is. What happens is that, in the same way that
pickle removes copper oxides from silver or gold, it removes the
calcium compounds from these minerals, leaving behind whatever’s
left over.

In the case of your Peridots, the only possible remedy is a complete
recutting of both stones, since you’ll not only need to repolish
them, but actually remove as much of their ‘skins’ as were affected
by the acid leaching. If this just happened, you might want to start
the “healing” process by bathing the pieces in a jar of diluted
baking soda in water, just to get whatever acid’s still in situ to
stop working on the stones subsurface areas. I’m really sorry that I
can’t offer a ‘magic wand’ solution to the problem but, hey, look on
the bright side of this: with the education you’ve just received,
what are the chances you’ll do that again?

All the best, Doug Douglas Turet, GJ Lapidary Artist, Designer &
Goldsmith Turet Design P.O. Box 162 Arlington, MA 02476 Tel. (617)
325-5328 eFax (928) 222-0815 anotherbrightidea@hotmail.com


#7

Sorry but the peridots will have to be either repolished or replaced
(probably cheaper to replace). Pickle pots will eat up peridots
every time, also never put doublets in a pickle pot.

Matt


#8

Peridots should not be pickled. Sparex and sulphuric acid
(traditional pickle) will etch some stones, most notably peridot, as
well as glass,pearl, to some degree and I’m sure other stones.
Peridot etches quickly. I’m not sure if alum will etch…

Andy


#9
peridot is attacked by warm sulphuric acid

Has anyone taken advantage of this for decorative etching? Does the
peridot yust frost (attractively?)-- or, with time-- will it etch
down? Of course, I can try it myself, but if someone else already
has… Thanks! --Noel


#10

Try painting a monogram on the table and dropping into the pickle
for a few moments. Don’t use too hot a solution and the effect is
very interesting. I got the idea from trying to find a substitute for
a bead-blaster and it worked out great. I used nail polish but and
lacquer would probably work. I can’t say how long the design last
but the “damage” is permanent so if the stone is worn in a pendant
and not abused, it should stand up well.


#11

Regarding the idea of painting a design on top of a peridot and
frosting it for contrast, I omitted removing the polish/lacquer with
acetone as a last step. This will leave a polished design set on a
frosted background. I hope this makes the process clearer.