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Author Topic: Storing opals in water  (Read 1244 times)

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John Robinson

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Storing opals in water
« on: August 18, 2017, 05:29:17 PM »

I had an "expert" tell me I should always store my opals in water and I have, but I was reading a thread today that caused me to question that wisdom ( plus I lost all of the color from my volcanic opals and a fire opal that once was crystal is now discolored yellow. )
So when and what types of opal need to stored in water and what types will such storage harm?
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vitzitziltecpatl

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Re: Storing opals in water
« Reply #1 on: August 18, 2017, 06:33:24 PM »

Disclaimer here: I am not an expert.

My opinion: Let it dry out once to see if you have "healthy" opal, then put it back in water. The rough will be prettier in the water, and it's easier to pick out the next piece to cut. Except for any hydrophane, of course. Leave it all dry.

If you have Ethiopian rough, much of it is hydrophane opal. It loses it's color in water. Most come back fine but some will come back looking slightly different after they've been wet and re-dried. You can identify hydrophane rough by the way it will stick slightly to a wet fingertip - or the tip of your tongue if you use the ancient technique of rocklicking.

Robin and I have a variety of rough, and it's been stored both ways over the years. The only type that really benefits from storage in water is Virgin Valley. Different mineral makeup from other types of opal, and the majority of Virgin Valley will crack/craze/fall apart as it dries out.

Other types will crack or craze when dried initially - just less of it than Virgin Valley. Some opal will "never" crack, and some begins as soon as it begins to dry. Many cutters even hold their finished stones for some time after they're cut and polished just to make sure they're stable.

If you let your opal dry out to see what will or won't crack, your chance of cutting stable stones from between the cracks should be better than cutting rough that has never been dried. Once it has dried and cracked, throwing it back in water and then re-drying again won't matter. The stresses from drying have already been relieved.

There's also a school of thought that cutting and polishing "seals" the opal so it doesn't dry and crack. Well, we've had cut and polished pieces be fine for months - and then one day there's a crack. Sitting in a gem jar amidst many other jars, one of them just cracks for no reason. Well, except that it's an opal... .

ileney

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Re: Storing opals in water
« Reply #2 on: August 19, 2017, 08:09:30 AM »

In my opinion, letting virgin valley dry out is a mistake as much of it dies without water. Storing Ethiopian opal in water is also an error IMO,  not only because it loses color temporarily when it is wet, but because wetting and drying it repeatedly before it has been cut and polished will cause  lots of crazing and ruin some of  your hydrophone  opals. In fact, some people (Village Smithy Opals also had this experience) said if they cut them dry, they had better yield with less cracking ( for safety must be done with a respirator, outside, with every precaution not to get dust on your clothes, in your home or especially, in your lungs). In my opinion, when you are ready to cut them, first let the Ethiopian opals dry out slowly and naturally; don't warm or heat them. If the Ethiopians have cracks, make sure to break them along those lines before you cut them because even if you manage to cut them intact, they can eventually crack without warning. I do have some Australian Coober Pedy  opals that were stored on water for thirty years. I don't think they were affected one way or another, but I can't be sure. Good luck!
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vitzitziltecpatl

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Re: Storing opals in water
« Reply #3 on: August 19, 2017, 04:50:45 PM »

Yep, we have Virgin Valley specimens in glass bell jars that will never be allowed to dry out. The only reason to let it dry is if you just can't live without cutting one sometime before you die. You might get lucky enough to actually get a dry stable cab. We have ONE - and aren't the least bit tempted to try for two.

A miner we know from there said the best luck he had for getting solid finished pieces was picking through old tailings that had baked in the sun repeatedly. By then it had already fallen apart as much as it was going to, and if he found a piece big enough to cut he might get a cab out of it.

Thanks for posting the Ethiopian info. It sure can be pretty. We've cut it, but never really pursued it. 

gemfeller

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Re: Storing opals in water
« Reply #4 on: August 19, 2017, 09:18:37 PM »

Re: VV opal:

Years ago I spent 3 days mining with the owner at one of the original mines there.  He had an awesome collection of black opal pine cone pseudomorphs that he kept permanently in water.  I've never seen any black opal to compare with it -- full spectrum colors with awesome reds.

He lived at the mine during the summer and had a nice but somewhat primitive cabin.  I asked him about cutting the opal.  He laughed and said he tossed good pieces onto the tin roof of his cabin.  "Anything that makes it through the hot weather to Fall is usually stable and cuttable," he laughed.

 
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edgarscale

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Re: Storing opals in water
« Reply #5 on: August 20, 2017, 08:02:30 AM »

i have a jar full of mixed opal in water.  mixed australian, african welo and mexican fire opals.  except for the fire opals and the welos,  i couldn't know which is which.  thought about keeping them separate nowadays, but then it was throw them together.  so, how do you go to the next stage?    i'd really like to make a ring for da-hubby.
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edgarscale

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Re: Storing opals in water
« Reply #6 on: August 20, 2017, 08:06:24 AM »

i'd need step-by-step process.  if anyone has the time to walk me through this i'd greatly appreciate it.....  :Worthy: please  :toothy10:
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hummingbirdstones

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Re: Storing opals in water
« Reply #7 on: August 20, 2017, 01:31:27 PM »

I'm a little confused -- what process are you talking about?  Separating the types of opal or what exactly?  I'll help you if I know exactly what you'd like to do.   :icon_sunny:
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Robin

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Re: Storing opals in water
« Reply #8 on: August 20, 2017, 02:42:54 PM »

need help not on sorting the opals but once the opals come out of its water bath.  how do i prevent the opals from crazing?  what do i use to treat the crazed opals, if any? what polishing agents and types of grit and tools are used to make a cab? 
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John Robinson

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Re: Storing opals in water
« Reply #9 on: August 20, 2017, 08:08:19 PM »

Thanks everyone. It sounds pretty encouraging the opals I have have all been out the ground for decades drying out and I only had one that was crazed. I am very glad to hear that I can get some color back once the stones dry out!
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hummingbirdstones

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Re: Storing opals in water
« Reply #10 on: August 20, 2017, 08:32:27 PM »

There are some people who will try to dry out the opals slowly with the hope that it will prevent cracking or crazing.  Personally, we dump out the water and just let them dry.  Some will crack or craze right away, some may take a week, month or even a year.  Some will crack or craze when you start to work them (relieving stress from inside the opal).  Opal is a unique beast.  If an opal is going to crack, it will.  If it's healthy, it won't.  It's just the nature of opal.

Cabbing in another topic altogether.  I'll tackle that one tomorrow.   :icon_sunny:
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Robin

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Re: Storing opals in water
« Reply #11 on: August 21, 2017, 06:55:17 AM »

the opal once crazed, can you use them for ..lets say inlay? when crazed do you need to treat them and how would you treat them?
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hummingbirdstones

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Re: Storing opals in water
« Reply #12 on: August 21, 2017, 03:06:58 PM »

I don't know of any treatment for crazing in opal that has been successful.  Years ago there was talk of some guy who claimed to be able to do it, but I don't remember who it was and never saw any proof that he accomplished it.  You can cut smaller opals from the rough if the crazing is minimal.  If the inlay is in very small pieces, that would maybe work.  Generally, though, once it's crazed, it's pretty much worthless.  You could always break it up into little pieces and make a gem jar or floating opal jewelry with it.   :icon_sunny:
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Robin

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Re: Storing opals in water
« Reply #13 on: August 21, 2017, 06:15:42 PM »

thank you for your advise on the crazed opal.  i will use it for inlay and floating jewlery (both sealed in resin).  they sound appealing.  i also do wood carving and would incorporate it.  adding as an (crushed) eye into my stone carvings sounds good too. i see a walking stick carved in snake motif with opal skin flakes.  hmmm, the more i think about it the more it can be added to anything.   maybe i'll play around and invent a way to treat crazed opal .  i might even get called "the crazed opal lady"...lol 
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ileney

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Re: Storing opals in water
« Reply #14 on: August 22, 2017, 09:07:23 PM »

If the opal is still really lovely despite the crazing and is Australian, you could probably preserve it with Hxtal, but it would have to be disclosed and most likely only worth 10 cents on the dollar or so, even if it looks great.
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ASO

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Re: Storing opals in water
« Reply #15 on: September 13, 2017, 11:25:22 PM »

If your not wearing a opal regularly the most important thing to worry about is storing it in humidity not necessarily water.  If a Ethiopian opal is stored in water it can actually help it to crack, I have seen this happen personally.  Something I have seen in Australia was the effects of very high end stones being stored in vaults that were designed to preserve important documents buy removing humidity in an already arid environment and all the moisture got sucked out of the stones drying them out and cracking them.  In a situation like this a opal should be placed in a sealed container with water in a vault and I believe this is where allot of these myths stem from.  In most parts of the world on any given day the air has enough humidity in it to not cause any problems with quality opal.
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gemfeller

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Re: Storing opals in water
« Reply #16 on: September 24, 2017, 08:42:17 PM »

Absolutely do not store opals in bank vaults without precautions as mentioned.  The dehumidified air is almost certain to craze stones.

As mentioned, "most" climates allow opals to aspirate any moisture needed for stability that's lost due to evaporation.  But a change of climate can damage some stones. I cut a nice opal for a gold pendant I made for my mother many years ago.  When she passed it went to my daughter.  It had been stable for many years until she took a job in far southern Arizona.  In just a few days the ultra-dry air caused it to craze.

The difference between "healthy" and "cracky" opal is a fine line.  I spent a few days mining opal years ago with the owner of the Rainbow Ridge Opal Mine in Virgin Valley, NV.  We worked in an underground shaft where the opal was found in a very wet montmorillonite clay where it remained stable.  He showed me how freshly-mined pieces began to craze immediately when exposed to sunlight -- you could hear the tinkling sound as the crazing proceeded.

But stable and cuttable opals from the same source could be found by winnowing mine spoils that had been exposed to the elements outside the shaft for several years.  The crazing appeared to be caused by too-rapid evaporation of water from the stones. But buried in the spoils, some of the opals seemed to lose water slowly enough to avoid crazing and stabilized. While the vast majority of VV is cracky, it illustrates a larger point about opal in general.  The secret of stable opal appears to be a balancing act of retaining a precise amount of water, and resupplying any lost to evaporation in the exact amount needed.       

     
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