Some say store opals in oil, some say in water, some say neither
Opals contain a small amount of water as part of their structure,
but it’s bound physically, not chemically, like water in a sponge.
So in cases where opals have a higher water content, some can be
prone to cracking or crazing if they dry out. This tendancy is
generally related to the location the opals came from. Most
Australian stones are quite resistant to spontaneous crazing, since
the water content is not high.
Some, like Idaho opal, are so high in water content that it’s almost
impossible to cut a solid stone and expect it to survive any length
of time without crazing. (These can be used to cut triplets
instead). And some, like mexican fire opal, falls in between,
meaning some will crack, others will not.
If you store opals in water, then obviously while they’re in water,
they won’t dry out. But this won’t restore opals that have started
to dry out, nor prevent future problems. Most folks using the stones
store them in air, in either stone papers or other sorts of displays,
or zip locks, or whatever. The main thing is to store them in decent
conditions. Don’t put them in a sunny window display case where
they’ll get hot, for example. But other than that, no special
measures should be needed. Among other things, in the event that an
opal is going to craze, it would be better that it happens while it’s
in your inventroy still, rather than after some customer buys it and
then is dissatisfied with your merchandise. So having the stone in
your inventory for a while can be viewed as proofing the stone…
You read now and then about storing opals, especially loose ones, in
oil. You can do that if you wish, but all it does is get them oily.
Doesn’t protect them, and can, if the oil isn’t clean, penetrate
matrix areas or cracks, carrying in dirt or whatever, and once it’s
done that, you’ll have a hard time cleaning it.
One thing sometimes used, that is very much NOT a good idea, is
glycerine, which one other poster, I notice, actually suggested.
Glycerine is hydroscopic, meaning it strongly attracts water.
Storing a stone in glycerine is about the same as putting it in an
extremely dry desert environment, and maybe worse. That’s just
begging the stone to dry out and craze.
46or my part, I figure this is a gem intended for use in jewelery,
which I expect my customers to be able to store and use in a normal
manner. So that’s how I store my stones as well. Mine are in the
little plastic foam filled gem boxes. Any that don’t survive are
either recut or tossed. Not many have met that fate over the years,
and I’ve had some, obviously poor sellers, that have been in that
display case for over 25 years, with no trouble other than the fact
that I’ve not made money off of them…