October is here. Images of falling leaves, jack-o-lanterns, and
little goblins running around collecting goodies abound. This month we
will explore taking the “fright” out of shopping for jewelry. Our
first weeks newsletter, however, always addresses the birthstones for that month, and this week we will learn more about opal, Octobers
birthstone.
Caring for Opals Opals are one of the toughest gems to keep looking
their best. Sometimes they lose thier luster due to small scratches on
the surface of the gem. These can be repolished by a lapidary to renew
a glossy surface. However, many times opals will seem to just lose
their fire. This is due to dehydration. Every so often, take a small
jar and fill it with distilled water. Place your opal jewelry in the
jar, under the water and let it soak for a few days. Think of it as a
spa for your jewels! This should help rehydrate your opals and renew
some of their life. This is especially vital in very dry or hot
climates!
Um, Guru, you need to recheck your gemology here. While many sources
of precious opal produce material that can be prone to dehydration as
you suggest, the vast majority of commercially sold opal is NOT
capable of reabsorbing water to correct the situation. There is one
variety of opal, called hydrophane, who’s structure is such that it
can dehydrate and then rehydrate. This was more commonly seen in the
opals from Hungary, common before the Australian finds were made,
leading to persistant stories of this type being applied to all opals
on the market. But today, hydrophane is quite rare, and other types
of opal do not rehydrate when placed in water. Storage in water will
prevent dehydration while it’s soaking, but won’t prevent it later.
On the other hand, if the water has a little dish washing detergent in
it, you’ll end up with cleaner jewelry after the soaking, which often
is a good thing, since simple dirt is often also why stones (not just
opal) can be looking a bit dingy. Also it should be noted that one
of the hallmarks of much of the Australian opal on the market is that
it has (for opal, at least) a relatively low percentage of water in
it in the first place. Many of these stones, once polished properly,
are quite stable and resistant to dehydration, and won’t exhibit
problems at all, even over extended time, so long as normal cautions
are used such as preventing excessive heating, freezing, or other such
stresses. By a very wide margin, the usual cause of opals starting to
look dingy (but not cracked, which is dehydration as you suggest) is
simply that because they are relatively soft, they’ve gotton scratched
up a bit, or perhaps are just dirty and need some gentle cleaning.
Peter Rowe G.G. etc.