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Care and storage of opals


#1

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I was reading some excerps from Gem Dealer’s Secrets and since I
work with opal a great deal I started reading that section. One
thing struck me that I thought I’d pass on and clarify if I could.

There is always controversy about the proper use, care and storage
of opals, but I believe the most recent suggests that
storing opals in glycerine, as the book suggests, is now out of
favor. Some recent material I’ve read even suggests that it may in
fact leech water from the opal.

I must admit I have no firsthand knowledge of this one way or
another, but in case someone decided to use that storage method, I
thought I’d note the controversy about it. Whether it’s useful to
store opals in water or not I don’t know, but I’ve never read or
heard that suggests that water can hurt them.

This email in no way suggests that this is not a good book and
valuable to have so handy and we certainly appreciate that it’s
here.

Derek Levin
www.gemmaker.com


#2

I’ve heard that using glycerine can make opal color more
cloudy…less sharp. Storing it in water, while preventing new cracks
also makes it very hard to see if there are any cracks, especially in
the rough, when you take them out to cut them. You actually need to
let the piece dry a bit before cutting it so you can look for cracks.
I’d actually suggest that rough could be stored in a closed jar with
a little water in it…keeping it moist, but not submerged… I
store my cut opals dry, but periodically soak them in water
overnight…maybe every year or so.

Jeanne


#3

I work with opals a great deal as well, and I’d always been taught
that water is the only medium in which to store opals. Glycerine,
indeed, will draw water from the opal by osmosis, and is to be
avoided.

Jackie


#4
 I work with opals a great deal as well, and I'd always been
taught that water is the only medium in which to store opals. 

Maybe I’m wrong, but this seems like just postponing the inevitable.
If an opal is going to self-destruct out of water, what is the point
of setting it at all? Are you going to tell the buyer to keep it in
water when it isn’t being worn? I keep the opals I buy in with my
other stones, in “normal” (fluctuating) conditions. If they hold up
for at least half a year, I feel comfortable setting them, though
most opals I actually store for at least a year just to be safe. I
have had some opals I’ve had for many years suddenly craze, but you
can only watch over them for so long…

Is there some flaw in my logic?

–Noel


#5

I have to admit that I’m not sure I understand all that I’m suppose
to about all of this, but would some one answer for me this, do
opals really deteriorate when mounted in jewelry? While in the ground
opals aren’t constantly in a liquid. I have several jars of raw opals
and have always kept them stored in water, but is this really
necessary or just myth?

Ray


#6
    I have to admit that I'm not sure I understand all that I'm
suppose to  about all of this, but would some one answer for me
this, do opals really deteriorate when mounted in jewelry? While in
the ground opals aren't constantly in a liquid. I have several jars
of raw opals and have always kept them stored in water, but is this
really necessary or just myth? 

Ray, perhaps the main problem in understanding this subject is the
thought that all opal is the same thing. The reality is that there
are many different types of opal, it occurs in many different ways,
and in many different levels of stability. Some opal is inherently
more stable than others, some is not.

If you want to know which of your rough opal won’t crack or craze,
take them out of the water for a year or two. If cracking or crazing
doesn’t occur by that time, chances are it won’t ever - at least not
under normal temperature/humidity/barometric pressure circumstances.
A sudden variation in any of those elements can cause dire
consequences. Opal that is in the ground isn’t subject to those
variations. Subterranean temperature, humidity and pressure are
usually fairly constant, so there won’t be the kind of shock present
to craze them.

Do opals deteriorate after mounting in jewelry? Some do, some don’t.
How can you tell if they will? You can’t, really. Mount them anyway.
You’ll know soon enough.

Opal is not for the faint of heart. Keeping rough opal stored in
water is a great way to keep it “hydrated,” but it won’t stabilize
them. Take them out and wait. Or take them out, cut them, and wait
(I prefer to cut them as I am of the "cut opal is sealed opal"
school of thought). It’s the only way to KNOW. And I do suggest you
polish the backs, as well as the tops. Those of us who believe that
a fully polished opal (front and back) is more stable will always
suggest it. It’s open to argument, but I polish the backs of every
stone I cut anyway. Why do half the job?

James in SoFl


#7

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 If you want to know which of your rough opal won't crack or
craze, take them out of the water for a year or two. If cracking or
crazing doesn't occur by that time, chances are it won't ever - at
least not under normal temperature/humidity/barometric pressure 
circumstances." 

Thanks James. I agree with most of what you’ve said.

I’ve cut a lot of opals from different places.

First an observation about stability without any foundation but my
own experience. It seems like the clearer the opal the stronger the
chance of being unstable. That doesn’t mean that all clear opal is
unstable but I suspect that it is more likely in clear than more
opaque varieties like white or black. As to crazing when out of
water. I think to be even safer, it’s better to cut the stone first
before setting it aside if you think it might be unstable. What I
mean is the rough may be stable, even dried for a while, but cutting
can change internal stresses and it could still crack. That happened
to a stone I cut once. That all having been said. Except for opals
from a few locations, I don’t think instability is that major an
issue. Mexican Cherry opal can be unstable, Ethiopian opal is often
unstable. It would be interesting to find out what other people’s
observations might be. What kinds of opals people might have had a
problem with and which have no problems. There is so much hearsay
with this opal situation.