How Much Do Opals Cost?

[Nicest_of_the_Damned]

@Cartooniverse

Undoubtedly " Damn you, Damned " will crop up now and again.

I can take it!

Here’s an opal question- since they are so very fragile, do they hold up for centuries like other cut/shaped stones or once dug up and worked by a stone cutter, can they fall apart if left sitting in, say, a museum display case or jewelry box for 10 or 20 years?

Must they be kept lubed in order to stay intact?

I have never seen this answered explicitly, but based upon what I know, things like sharp blows and sudden temperature changes are more of a danger to an opal than simply drying out in storage. All other things being equal, I think a stone stored in a box in your home is probably less likely to suffer disaster than one in a ring that is worn daily. An exception might be if it were stored in a very warm area. And some stones are simply in better condition to start with, so that would also make a difference.

I have seen mixed advice regarding oils. Many sources do recommend it. Others say it does more harm than good. Some say soak in water, not oil. Still others say the stones are non-absorbant so soaking will do nothing, though I imagine it would still seep into any small cracks. I think it probably depends on the individual stone. Some people claim that regularly handling the stones is good for them, since some of the oils in your hands will be transferred to the stones. I have never oiled any of my stones or done anything special while storing them and I have never had one crack. I’d say the oldest ring I have is probably about 15 years old.

I imagine a museum would keep a close watch on humidity and other conditions that might potentially damage a valuable stone.

[Baron_Greenback]

@MrJackboots

Opals aren’t really stones, per se. They’re like superthick gels of silicon dioxide and water. A precious opal has some crystaline structure (lots of tiny crystal sphereoids held together by water), but as the water leaves, that hold weakens, and the opal can become more brittle or even break apart by itself. There won’t be enough water holding it together, see.

Tomorrow, this piece of information will earn me a million brownie points with my mother. She’s been moaning for years about her opal jewellery deteriorating.

[Cartooniverse]

@Nicest of the Damned

I I have never oiled any of my stones or done anything special while storing them and I have never had one crack.

–biting lip-- Naw. It’s too easy. We try not to judge our fellow Dopers based on how often they oil their stones.

The reason I asked about oiling, water and so on is because of the peculiar composition of an opal. Any other stone, sure. Fairly stable, good to clean or oil or whatever. But the opal is trule made up of some percentage of water ( see cite, MUCH less than we thought ! ), and so its care and storage and handling seemed to be different.

I am amazed that the opal ring I gave to my wife hasn’t suffered a crack yet. She’s had it for 21 years and wears it a fair bit. She plays the piano daily, too.

[Nicest_of_the_Damned]

@Cartooniverse

–biting lip-- Naw. It’s too easy. We try not to judge our fellow Dopers based on how often they oil their stones.

:eek: Perhaps I should have started on a topic less controversial, like the war in Iraq, declawing cats or circumcision.

The information on oiling/soaking stones is all over the map. Like I said, I think it can really depend on the condition of the individual stones, I am not sure there is one correct answer. Some sites claim that only stones mined from certain locations should be oiled, but people rarely know where there stones come from. I just have not seen any source of info that has me completely convinced. I tend to be the type who does nothing when it doubt.

From what I can see, the biggest danger comes from storing things for a very long time, particularly in extremely hot or dry conditions (safe deposit boxes seem to have a history of causing problems). Storing them under your average home conditions seems to pose less of a risk. But when I have had my rings for a hundred years or so, I will let you know how they look!

[Nicest_of_the_Damned]

Hmmm…looking at your own link I see:

Opals can also absorb fluids, and should not be brought into contact with detergent or oils.

Also see the section on opal care:

http://www.opalhouseltd.com/Opal%20Care.htm

It says that they do not need to be rubbed with or soaked in oil or water, but…

You can believe that:

a) you can leave your Opal safely in a vault or safe without a water bowl for long periods.

b) every Opal loves to be worn. The natural oils from the skin only enhance the Opal.

(Are letter lists exempt from the three-item-rule?)

The GIA (Gemmological Institute of America) site does not mention soaking or oiling.

http://www.gia.edu/library/15534/featured_gemstone__opal.cfm

Stability

High heat or sudden temperature change can cause fracturing. Opals are generally stable to light, but heat from intense light can cause fracturing (known as “crazing”). Opals are attacked by hydrofluoric acid and caustic alkalis. Loss of moisture, and crazing, can result from storage in airtight containers, such as safe deposit boxes.

I am still not sure I see any evidence that oiling should be the default procedure. You say your wife has not had any problems with her opal after more than twenty years, does she oil it?

[ralph124c]

Are synthetic opals good looking? anyone ever see one/

[Enright3]

@CalMeacham

Hi, Opal!
…Well, you knew somebody was gonna do it.

I frequently play a mental game where I think of a predictable response and ask myself how many posts will be made before that response is made.
I have to admit, CalMeachan, yours didn’t occur to me, and it should have. Instead, I was thinking someone would provide a link like this.

I’m not worthy of being on the SDMB today.

[lizardling]

Interesting thread! My uncle’s an occasional itinerant opal miner in AUS, and ended up giving us small opals when we were young. I got a black opal that was a tetch larger than my last pinky joint. It’s got a lot of pits in it, so I’m guessing it’s not that high quality an opal.

I should pick it up next time I’m in Texas, as I put it in a small case for safekeeping away from light and most air, and have it looked at by a jeweler to see what they could do with it. I don’t wear jewelry much, so I’m not sure about it, but it is pretty.

[Nicest_of_the_Damned]

@ralph124c

Are synthetic opals good looking? anyone ever see one/

I started seeing a lot of these just as I was getting out of jewerly sales, towards the end of 2000. It was all labeled “synthetic opal” but my understanding was that it was not a true synthetic, in that there were some significant physical differences between it and the natural stuff. All the stuff I see in supply catalogs these days is labeled “imitation” not synthetic.

I did some googling to see if anything had changed since then and I found a couple of interesting articles:

from 2001:
Synthetic or Simulant?

Lawsuits Ignite Furor Over Created Opal

I am not sure what the outcome of the lawsuit was. A search for “synthetic opal” shows that a lot of people are still selling it using the term. Interesting that the chief argument against calling it synthetic is that it does not contain water, which as we have been discussing, is something of a liability. As far as I can tell, no one has yet produced a true, lab created synthetic, but I admit I have not really been following what is on the cutting edge of gem synthesis.
The stuff I was seeing in 2000 was used in a lot of southwestern Native American style jewelry, lots of inlaid work. What I saw was quite eye catching and very popular. However, it all looked the same and didn’t have nearly the range of patterns you find in natural opal. It had a white background and didn’t show the large patches of color. It had all over, very densely packed pinpoints of color, very flashy.

I would say it looked very nice, but perhaps a bit “too good to be true” if you know what I mean. I thought it had just a bit too much of a “candy” look, but most people didn’t realize it wasn’t natural. I would bet a lot of synthetic opal is passed off as natural opal, probably often through ignorance. But this was several years ago, perhaps people have become more aware of synthetics since then. It was less expensive than what you would expect to pay for natural opal of that quality, but still not cheap like costume jewelry.

I have also seen it offered in black in catalogs, though as far as I know, I have never seen that in person. A little googling shows that there are some suppliers selling the more “patchy” patterned stuff, in many colors.

Going back to about 1994, I worked at a shop that was selling something labeled lab created opal. It was translucent and slightly milky. It had bright, shifting flashes of color inside the stone, sort of like a hologram. It had this very beautiful, other-worldly look, but it didn’t look anything like what people normally think of as opal. A few pieces were even faceted. I haven’t seen anything quite like it since.

There are also lots of other lower quality simulants out there, made out of foil, glass, plastic, etc.

Some comparison photos here:
http://www.cigem.ca/inclusion/op01.html

[Leaper]

I’m impressed.

I was sure the Opal jokes would start on the SECOND post. Nice self-restraint, SDMB!