The only stones I’ve heard should not go in an ionic cleaner are
drusy. I’ve never put any drusy in my ionic cleaner to test that
theory, but I do know that the druse crystals tend to be very
fragile. I’ve cleaned every other stone I’ve ever worked with in my
ionic cleaner, and always get wonderful results. If it helps, I have
an article about cleaning jewelry, although most artists on this list
probably know this info:
http://www.home-jewelry-business-success-tips.com/cleaning-jewelry.html .
Take care.
Rena
http://www.rena-jewelry.com
... but I do know that the druse crystals tend to be very fragile.
From what I’ve been able to learn online, ionic cleaners are "safe
for soft and fragile gems like Emerald and Opal, as well as Diamond
and all other (including pearls). So if druse crystals
are especially vulnerable to ionic cleaning, it would have to be
because the ionic action somehow loosens the attachment of the
crystals to the substrate. But since ionic cleaning does not involve
vibration (or destructive chemical solutions), that seems unlikely to
me.
The type of druse involved could also be relevant. The most common
is composed of quartz crystals on an agate substrate – not fragile
at all (if you discount impact damage; dropping it on a hard floor
would probably not be efficacious :-). The softer or more brittle
druses, like uvarovite or cobalto calcite or azurite, might be a
different story. Beth