Is this what you'd call a crazed opal?

[beaujolais]

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120897081999&ssPageName=ADME:B:SS:US:1123

scroll down a bit to the second picture

Thanks.

 

[innerkitten]

I think so. I've seen stones look like that but more pronounced before.

 

[chrono]

Looks like it to me.

 

[jeffdvs101]

@ $12.99 including a ring! what are you really expecting?

 

[ChrisA222]

Well...I thought that the Welo/Etheopian Opals were stable and immune to "crazing". Correct me if I'm wrong, but I believed crazing to be when the Opals "dry out". But I thought this was only for the Fire Opals..solid colored stuff. Everything I had read about the Welo Opals said that they were stable.

If anyone knows for sure let me know.

 

[Quantz Studios]

EVERY opal is prone to crazing- None are immune. Some are less susceptible to it, but ALL can craze. Crazing happens when the opals amorphous structure loses water content and it's structure undergoes stress and weak points which eventually give. It's similar to when drying mud develops a cracked surface. Crazing mostly depends on the water content of the stone. If the precious opal from northern Nevada (Virgin Valley) had less water content and was more stable, Australia would be replaced as having the finest opal. VV opal's water content is just too high. In contrast, the Brazilian material has historically been regarded as the most stable opal. It's water content is incredibly low to begin with, so losing any water it has wont do much to it. The earlier Welo material (early 2000s) is notorious for severe crazing. I'm sorry, but everything you've read on Welo material is pretty much the opposite of my experiences, as well as those of most others who have worked with Ethiopian opal that I know. The material coming out in more recent times appears to have improved over those earlier finds, in regards to stability.


The pictures in the link are horrible, it's hard to tell for sure but to me it doesnt look crazed. It just looks like a really poor quality piece with some inclusions that can be interpreted as cracks. If the first picture was more clear it'd be easier to tell. But it appears to have the white-colored, little dendrite looking features that I've seen a lot of in Ethiopian material. Fractures and cracks would stand out much more I think, they'd reflect more light. More-times-than-not, they stand out like a sore thumb. Regardless, I think you can do MUCH better on an opal for not much more money.

 

[beaujolais]

@ $12.99 including a ring! what are you really expecting?

Now, Jeff, I was only asking in order to learn! I've never seen a crazed opal but have heard of them.

Sometimes, I've posted pictures not because I'm looking to buy it, but for educational purposes.
---

Thanks all, for you help/opinions.

 

[Quantz Studios]

If you've never seen a crazed opal, I'll share a few pictures of my own of some stones that have crazed before or after cutting. They're all fairly easy to spot in pictures, and unmistakable when the pictures are clear.

These two are pretty obvious. Both are Ethiopian Welo opal. They're rough. Ethiopian opal soaks up water like a sponge. During cutting when it gets wet it soaks up water and goes transparent, water clear and some of the play-of-color goes away. After it's cut it starts drying out and goes completely opaque, milky white and unattractive for the most part. After a few days it goes back to normal and the play-of-color and body color and translucency return just as they were before. I soak all my rough in water before cutting it and let it dry out again for a month or so. 90% of the time, any crazing it's going to do is going to happen then instead of after cutting. Sometimes you can even hear it, like cracking ice!

 

[Quantz Studios]

This is an Australian opal, with crazing so bad it created several spots where the play-of-color completely disappeared and turned milky grey.


Here is another Ethiopian opal. It was one of the rare cases of a stone just committing suicide. I soaked it and it dried out, and crazed a bit. Then during cutting I cut the crack out, took a break and came back to a new crack in the same spot. It just kept going further and further in the stone and wouldn't cut out. So I gave up. I still finished the stone because of the killer pattern and color, but now it's just a specimen in my junk box. The crack runs north-to-south, starting on the bottom of the stone, about 1/3 the way from the left.

 

[beaujolais]

Thanks so much Stonebender (cool name, btw).

They sure are still beautiful in spots, though !

Some questions (that I should know but don't), if you would:

If you set one that is crazed, I guess it can crack more when setting or become more unstable and break if it does make it through setting?

What is the reason that a specific opal only does certain colors? Probably the minerals it contains?

Do Ethiopians usually give a better color play when set? (Meaning I've got two, that looked nice in the picture when I bought them, but in real life are a little underwhelming.

Should one soak their opals in water every so often?

Oh, thee searchlight pattern - I've only seen one, but it was really neat. They are not too common to find, right? Any suggestions as to where I could get a hold of one?

Thanks so much !

 

[Kim Bruun]

What is the reason that a specific opal only does certain colors? Probably the minerals it contains?

Actually, the colour play of opals is not a function of impurities (for example, when chromium is present as an impurity in beryl, it causes green coloration, i.e. emerald). The base colour is no doubt affected by the presence or absense of impurities, though.

Precious opal is amorphous, made up of regularly sized and stacked silica spheres, where light is scattered by the network of voids between the spheres - the result is the colour play for which precious opal is famous:

Larger spheres produce a complete spectrum as the opal is tilted, but small spheres generate only blues and violets.

Source: GEMSTONES, Christine Woodward & Dr Roger Harding, British Museum (Natural History) 1987.

 

[beaujolais]

Thanks Kim.

Actually, the colour play of opals is not a function of impurities

Still, why do some opals do certain colors (in their color play, not base color) than other opals?

 

[Enerchi]

I second the "thanks for posting, Stonebender"! Those are very educational photos - are you allowed to post more? Please do if you can!

Opals are so fascinating. I have a few that are very old stones, I'm interested in your reply to sonomacounty above, about how to best care for them.

 

[Kim Bruun]

Still, why do some opals do certain colors (in their color play, not base color) than other opals?

Read the second paragraph + the citation in my post above.

 

[Quantz Studios]

Kim was right on the cause of the color play. It's diffraction of light between packed microscopic silica spheres in layers, which split light into its spectral colors. The better the spheres are organized or "stacked" , and the the more uniform the size of the spheres, the more regular the patches of color will be. Picture a box full of ping pong balls neatly arranged in a layer, put a sheet of transparent plastic over them with a small layer or marbles on top of that- That's kind of the structure of opal. The colors flicker on and off as you move the stone because you're changing the angles and which the light enters the stone, altering its path inside of the stone. If there is no uniformity of size and how they are stacked there will be no play of color- It will only be common opal or "potch". Only certain sizes of spheres will produce color. Smaller sphere's lean towards the blue end, and larger ones make up the red end which the yelloes and greens make up everything in between the blue and red. Anything smaller or bigger than that range, there will be no color. I could give specific numbers, but I'm too tired to dig out the books. We're talking nanometers. I think 2nm-8nm is the color-play range. Purple is a rare color in opal. Purple only occurs when a layer of red-sized spheres overlaps a layer of blue-sized spheres. Or the other way around. (Red and blue make purple. ) Common opal's spheres are irregularly stacked and not of the same sizes so little or no diffraction takes place. Light is just pushed through and scattered around a bit between the spheres which causes the milky haze most opals have- that is opalescence (a specific term given to adularescence in opals). In common opal, the body color is influenced by trace minerals, or microscopic inclusions. I am a nut for opal, it's one of my top favorites. but it's been a long time since I've read up on them or explained this to anyone so forgive me if it's not thorough enough.

As for setting a crazed opal- I avoid it. I refuse to finish cutting (with a crack), sell or set 99% of crazed opals. There are too many things that can cause a full failure of the stone and really come back to haunt me. It's just a bad idea. Thermal expansion/contraction can worsen the crack to the failure point. Even the slightest knock can split it the rest of the way. Even left alone the crack can continue to grow on it's own. Pressure from setting CAN crack it more or make it fail. I just cant sell or set a crazed stone- It makes me look bad as a cutter, and a customer might not be so understanding if the darn thing decides to fail when i drop it in a bezel. There ARE exceptions, of course, as in this Oregon opal I cut a long time ago with my Dremmel when I first started cutting stones. It's like a natural triplet; The top layer is stable transparent, colorless opal with a bottom layer of stable, milky white opal and in the middle is a layer of crazed opal that is in the middle of the two in transparency. No color play, but an amazing stone to look at. This one is forever in my personal collection and will not be going anywhere. Forgive the ancient picture taken through my loupe! lol I REALLY need to take better pictures of this stone.


This is an exception as well. I got this rough in 2007 from a guy at the Denver show who pretty much was going to throw it out as junk. It's a Mexican opal, with color play. But the color play is enhanced and reflected among the network or cracks running through the stone. Like with the last one, there is a layer of stable, yellow opal on the bottom of this one. Sort of a natural doublet. I cut the outside shape, but the divot on the top in the middle is a natural conchoidal fracture surface. I dropped it, beat it around for a bit to ensure it was stable enough. I sold it a year or so back, with a strong understanding from the buyer of possible breakage. But it's more of a specimen; a curiosity, because it really is a fantastic stone to look at.


There are always exceptions... But in general, it's a good idea to stay away from crazed opal. Not so much in rough form if they are at a minimum. But cut, I stay away. There are enough stable opals out there.

The only way I know of any opal improving in appearance after setting is if the backing of the stone, or the back of the stone itself is made darker. Like with paint, or black marker, or even a backing as in a doublet/triplet. In general, most opals that trend more towards semi-transparent and transparent look better on a dark background. Not always true. There are some amazing crystal opals from Australia that look amazing no matter what their background is. I've found that if put directly on a light surface, most semi-transparent and transparent opals will lose some of their contrast. Even if you raise it up slightly off the surface the appearance improves. But if the color play is bright enough it wont matter. So, only by being backed somehow by something dark or black, with any opals color play improve when set. Yours probably looks different in person because opals are pretty hard to accurately photograph. I spend a lot of time getting my current opal pictures as true to life as possible. It takes a lot of fiddling with settings, lighting, background and light types. Most times, pictures deceive when it comes to opal. They either look better than they really are, or worse- Especially (better-looking than IRL) if the stone has weak color play and was photographed on a dark background. That, or I hate to suggest it, but you were shown a stock photo of an opal of the same shape and size, and not sent the actual stone photographed.

I avoid ANY opals stored or soaked in water or oil. Bad. Oil soaks in and degrades and decomposes, it discolors the opal. Opals do not need watering. However, It is NOT a good idea to leave them for years at a time alone in a safe-deposit box. They need the occasional washing and contact with the oils in your skin. This will prevent them from drying out too quickly or at all. Storing opals in water acclimates them to a certain humidity and once taken out of the water it dries out and becomes a shock to the stone. I could be wrong on that, but thats what I was taught. I only know my personal experience from cutting opals and owning some. I dont baby them, not at all. Some die on the way to the end product, but that only weeds out the weak ones and ensures that I have the best of the bunch. Yes, opals need some care. But it is still a rock. They are more durable and stable than a lot of people really know, actually. You just do your best to take care of it, touch it and not let it sit in too dry of an environment for too long. I have a inlay opal ring I made for myself. I've been a woodworker, an auto mechanic, a tile setter, plumber... I cut stones and make jewelry and artwork wearing it... I've done a lot of hard labor with that ring on. I've beat the crap out of that ring and not treated it any different than a plain band, and the opal is still 100% fine as the day I put it in. Yeah i've repolished it twice over the past 6 years, and did drop it on a tile floor at McDonald's in Beaver, UT that put a crack in it that you can barely see. But it's held up longer and better than anyone ever expected. I'm getting off on a tangent... I'll stop. I just love opal.


Please explain a "searchlight pattern" in opal. I dont think i've ever heard of that. There are many, many different patterns in opal. Some are VERY rare.

 

[chrono]

A very informative thread which I am almost tempted to request it be re-written as an education thread alone, where others are aware of the topic and can ask questions. I know sometimes we gloss over topics that do not look particularly interesting to us (at least we mistakenly think it is).

Why do opals look better in pictures than IRL? Take a look at the background. Is it dark or light? Like almost all gemstones, the background colour of the photograph affects the perceived saturation, and in this case, colour play, of the gemstones. To amp up the colour play of opals and moonstones, usually a black backing is introduced in the setting.

 

[beaujolais]

Smaller sphere's lean towards the blue end, and larger ones make up the red end which the yelloes and greens make up everything in between the blue and red.

That is exactly what I was looking for.

Now, OMG, Stonebender/Ryan, I can't thank you enough. I need to go study that for a few hours. You are Awesome.

The Oregon opal & Denver show opal are fascinating. I think I could stare at them for quite a long time & often.

Um, I do agree with Chrono that something should be done with that wealth of information you so kindly wrote. That is too valuable to not have a special spot for reference.

Searchlight opal: https://www.pricescope.com/community/threads/what-kind-of-pattern-does-this-opal-have.156954/

The links to that stone are gone, as it was awhile ago. I have a horrible habit of when I find something great on e-bay, I either fall asleep or misjudge when it is ending.

Some had called the above e-bay link, in the above Pricescope thread a ribbon pattern. I looked up ribbon opal, again, and the one I was looking at on e-bay did not look like the "ribbons" I've seen. This one (the e-bay stone) had random thin color streaks. Sort of like short strands of string laid down randomly.

If you would, do most Ethopian opals get better when set rather than loose? I think I've heard that.

Again, I can't thank you enough.

I just looked at your gemstone business, which can be found on Etsy, Facebook at Cut Gemstones by Ryan Quantz and a few other places (?) Way cool. And you are so young, too ! You go Ryan !

Sonoma

 

[Quantz Studios]

That is exactly what I was looking for.
Now, OMG, Stonebender/Ryan, I can't thank you enough. I need to go study that for a few hours. You are Awesome.

No problem. If anything more specific is needed, I can bring out the books and see what I can dig up.

Searchlight opal: https://www.pricescope.com/community/threads/what-kind-of-pattern-does-this-opal-have.156954/
Some had called...a ribbon pattern. I looked up ribbon opal, again, and the one I was looking at on e-bay did not look like the "ribbons" I've seen. This one (the e-bay stone) had random thin color streaks. Sort of like short strands of string laid down randomly.

Do any of these patterns resemble the pattern you speak of at all? Of course... With Aussie opal there is a set chart for patterns. But talk to 10 different opal experts and i'll bet you get 14 different descriptions of each pattern, and requirements of a stone meeting that pattern. Some of those patterns dont carry over, among the experts, to Ethiopian opal despite what people will try to sell you. TRUE Harlequin pattern gems are few and far in between, but with the arrival of Ethiopian opal, it seems harlequins are everywhere. Ethiopian opal has some unique patterns. They are plentiful too. Even moreso are the descriptions, and everyone's interpretation of them. It can get confusing. For example, the triangle apex-domed Ethiopian stone I posted above that is fractured... doesn't fit into any of the patterns listed on this chart... lol Anyways, I'm rambling again. (Chart taken from OpalAuctions.com for education purposes, this is not my image and I claim no rights to it. )

If you would, do most Ethopian opals get better when set rather than loose? I think I've heard that.

As Chrono and I explained a bit above, i've never heard of or seen any kind of opal improve in appearance with setting except for when the back of the stone or the setting behind the stone is turned black by a number of methods. It's possible that in a faceted piece, the metal surrounding the stone can increase the amount of light going into the stone. But, that can either improve appearance by putting more light into the stone for color play, or detract from the appearance by putting too much light into the stone and drowning out or dulling the color play by illuminating the body of the stone more than usual. Either way, if one didn't pay very close attention they probably wouldn't be able to tell any difference loose vs. set. I'd have to say what you've heard isn't true. But I am just going on whats in my experience. Most opals cut "en cabochon" are opaque, the rest are translucent or semi-translucent. The semi-transparent and transparent stones would be the most affected by a setting, if at all. Those are likely faceted and probably wont be much affected at all unless the color play is weak and cut en cabochon. The opaque, translucent and semi-translucent stones: I highly doubt that any conventional metal put behind or around one will influence the stones one way or the other. As I've said, I could be wrong, but in my short experience I have yet to see an opal changed for better or worse after setting. Unless, of course, there is black put behind it.




I do kindly thank you for the compliment, too

 

[iLander]

I have a question; what exactly are opals? What were they before they were opals?

 

[Quantz Studios]

Opals are a hydrated, non-crystalline quartz. To keep it simple, they are a sedimentary deposit where silica-rich volcanic ash and tuffs are weathered, the silica and other minerals are carried by water into cracks and fissures in the ground where they settled and solidified over periods of hundreds-of-thousands of years or more.

 

[beaujolais]

So, to put it as simply as possible - sand in quartz?

Now, I apologize if it seemed like I asked somethings more than once. Actually, I was looking for even more detailed information, which I did get upon re-asking. As, you, Stonebender, told me how each sphere's sizes give which color. Thanks to Kim also, then Stonebender filled in the other sphere sizes for the colors.

Re: better when setting. Chrono (another wealth of information & help) did explain that they may bet better with dark backings. I wasn't sure, still how it would perform when set in prongs. Seems they would probably stay the same? (Translate - I've got two Wellos in gem jars that are a bit underwhelming and am trying to figure out what to do with them. I've yet to try them on darker backgrounds or in a pick up tool - I guess because they are kind of sad little stones & I've been ignoring them.)

Thanks, again, SB, for another great photo. The e-bay stone was none of those patterns but closest to the Welo Ribbon Mackerel. The pattern of the e-bay stone was something like, say if you take a piece of paper, then cut up cooked angel hair pasta (I'm trying to say the ribbons were rather thin) into several inch long pieces. Lay pasta down on paper in a slightly random pattern (but with more of the pastas going in a similar direction). Funny description but that is the most accurate I can come up with.

I have to find another of those searchlight stones, one day (sigh).

SB, which are your favorite patterns? Least favorite? Color preferences for body color & play of color?

Oh, question - on some opal sites I see stones that do only blue & green color play. To me, these are not appealing. People do like these or not so much?

Again, many many thanks!

 

[beaujolais]

SB, one more thing, can you recommend any books or websites on opals?

Tx.

 

[Barrett]

Is this what you'd call a crazed opal?

Nope, but this is what you would call a CRAZY opal!
Sorry for the thread jack but my friend Fred, who I saw at Jackson Crossroads Amethyst mine on Sunday, had this opal set into his tooth. He makes crowns and fake teeth for dentist so when he needed a front tooth replaced he made this in the lab and had it put in. I asked him if it was at risk of getting damaged since opal is so soft but he said the front teeth recieve suprisingly little wear and tear so is perfectly fine right there. I got to see it in person on Sunday and he sent me this picture today

 

[Enerchi]

GET OUT!!! that is tooo cool!!!

Hope it is able to survive living in his crown!

 

[Quantz Studios]

So, to put it as simply as possible - sand in quartz?

No, no. Nothing to do with sand. This is quartz on a microscopic level.

Re: better when setting. (Translate - I've got two Wellos in gem jars that are a bit underwhelming and am trying to figure out what to do with them. I've yet to try them on darker backgrounds or in a pick up tool - I guess because they are kind of sad little stones & I've been ignoring them.)

Are they faceted or cabochons? Likely getting them out of a case, in the hand or suspended somehow will help. The non-opaque opals don't like being right up against a white background. Like I said above, if you even move them off that background only a little bit, they get less overwhelmed by the light background which drowns them out and projects that light color into the stone.

SB, which are your favorite patterns? Least favorite? Color preferences for body color & play of color?

I dont really have a preference for pattern. Of course, i'll take a harlequin over a pinfire pattern any day. I just like high quality opal with bright, full-spectrum color that covers the whole surface and isnt directional. I like darker body colors and crystal opal more than opaque white. But of course, as long as it's nice opal I like it. I dont care much at all for green/blue color play. I like full spectrum.

Oh, question - on some opal sites I see stones that do only blue & green color play. To me, these are not appealing. People do like these or not so much?

They are more common and therefore more affordable than full-spectrum stones. Some people really like them, some dont. I dont. But a lot of people do. Most opals i've been shown by friends and customers are these blue-green stones.

No idea on what websites I can show you. Sorry, I dont do a lot of research on the internet anyways.

But any book by Paul Downing is a good one. "Opal: the Phenomenal Gemstone" published by Lithographie LLC, is my favorite. I know there are quite a few fine Opal books out there, but the latter one I listed is the most recent and comprehensive over almost all known sources for opal. Others just concentrate on Aussie material. Sorry I cant help you more on that one.

 

[chrono]

Sonoma,
Remove your opal from the case and place it on the back of your hand between two fingers. Having it not against a white background will give you some idea. This will also simulate it in a setting. If they are really underwhelming, you should consider a backing.

Blue and green colour play in opals are common, therefore that is the reason why you see more of these around, not necessarily due to demand. This variety is also less expensive.

 

[MakingTheGrade]

That tooth is amazing!

I have a blue/green black opal that I love, reminds me of the ocean ad of Starry Sky. I really like the intense blue color, I actually dont care too much for the full spectrum ones as they seem a little but too busy and confetti like to me. I'm weird like that, but my wallet thanks me.

I have a question, is it common for opals to have inclusions? Do clarity grades even pertain to them? I almost never hear it mentioned in reference to opals. In my opal in certain lighting, I can see a little bit of what looks like sand, which I think is cool because it gives to effect of the stone looking transparent and more watery. I don't know what it is or might mean though.

 

[Kim Bruun]

Barrett, that photo reminds me of a story my mother told me. David Bowie (to the best of my recollection) apparently had an emerald inserted into one of his teeth at one point. He came to regret the decision when he was repeatedly told that he "had some spinach between his teeth".

 

[chrono]

I wonder how tight the space is between the stone and the tooth. It would be horrible to have the stone drop out and swallowed or cavity or placque build up in the microscopic gaps.