Opals

I don't know about opals. But, this site does.
http://www.opalsdownunder.com.au/articles/care.php

I don't know anything about taking care of opals - sorry Tomkitten. But, I enjoyed learning from that website!

They can be restored somewhat but not completely. The Mexican opal miners used to soak their stones in mineral oil to heighten the play of colr. This can be done by jewelers pressure chambers , but since opal can be in several layers, its amazingly delicate and can slough off with too much futzing. Id suggest that you get it cleaned and try the oil soak for a few days (no pressure0 and just live with the results.
Opals, without storge in optimal conditions, will always deteriorate in color play as the stone "dries out"
Since opals are composed of a lattice of silica and water, (and the water is in a form called a collapsing surface layer), they are always in an unstable condition and are really touchy.
I own a piece of Ammonite (opalized fossil shell)"bling" and Ive had it for about 20 years . Its losing its fire also and I should store it in an opal friendly environment.

Its entropy, deal with it.

As opal colour is a result of refraction of light through various mineral layers fine surface scratches can mar the original colour.

Repolishing by a suitable craftsman may have some effect, including if the stone is a doublet or triplet ie encased in resin.

Soaking in oil may have a temporary effect as this will infill fine scratches on the surface. Try wiping over with a cloth dampened with mineral oil, if the shine improves the stone may need repolishing.

Soaking in water will have no effect. Opal is imperviouse to water. Store the ring in a sealed plastic bag with a very slightly damp cloth to maintain humidity especially in dry atmospheres like airconditioned/heated homes. check regularly for mould. Mould will not harm your opal but it is unsightly.

Opals
Thank you everybody. I went to the website Intrepid suggested, and emailed them with a couple of further questions.

My opal is set in a silver ring, and was probably not very expensive, since it was given to me by my late husband when we were first married and being very careful with our money, but I would like to improve its current state.

Farmerman - entropy is as entropy does... If I can reverse its effect I will certainly try to do so. If not, then I'll take your advice and "live with it".

TomKitten--

Not to Cast Asperisions, but I'll admit to losing a little bit of my luster over the years.

Still, we regain that inner glow....at least in our own eyes.