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Post by MsAli on Oct 21, 2017 11:49:28 GMT -5
Was given these many years ago and I forgot where they said they were from. I want to say Ethiopia, but could be so off on that. Can someone tell me exactly where these are from and or what type? And what should I do with them. They appear very soft but I would love to expose the coloring if possible
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gemfeller
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Opal
Oct 21, 2017 13:31:36 GMT -5
Post by gemfeller on Oct 21, 2017 13:31:36 GMT -5
Can you tell us more about how you got them and why you think they're opal? The material looks to me like ironstone though images can be deceptive. Ironstone opal is associated with Queensland, Australia. There's a type of Australian ironstone nodule that can contain very beautiful precious opal called a Yowah Nut. The "nuts" are named after a town near where they're mined. But the shape of your pieces is quite different than any Yowah's I've seen. Yowahs generally have a fairly smooth exterior and an egg-like shape, as in the image below. Yours have a "botryoidal" shape, meaning the exterior form resembles a bunch of grapes. I've never seen precious opal like that and I've been an opal "nut" for many decades. But that doesn't mean it doesn't exist. That's why I'd like to learn more about your stones. Yowah Nus
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Opal
Oct 21, 2017 14:11:50 GMT -5
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Post by MsAli on Oct 21, 2017 14:11:50 GMT -5
I dont have alot of information on them just what was told to me. Ive had them for about 15 years and the gentlemen that gave them to me told me he was given them by a man that was an opal trader. I asked my ex and he said the guy said they were Australian opals. They are so odd and all my research, I cannot find anything that looks like them either. A man that sells gemstones told me they looked Mexican to him, he definitely said they are opals.
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gemfeller
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Opal
Oct 21, 2017 14:40:29 GMT -5
Post by gemfeller on Oct 21, 2017 14:40:29 GMT -5
I've been cutting, selling, studying and learning about opal for well over 50 years and there's nothing about those nodules that says "opal" to me. But I learn something new about that amazing gemstone nearly every day so if you want my opinion I'd say slice them in half and see what's inside. You might be delighted or disappointed.
The majority of Yowahs, for instance, are duds: ironstone all the way through. But some have nice opal displays and a tiny percentage have awesome opal interiors. There's little indication from the exterior either way.
I've cut lots of Mexican opals and there's nothing about your stones that indicates Mexican origin in my opinion. The "Quarry" opals (Canteras) are the Mexican corollary to Australian ironstone or "boulder" opals and they have an entirely different appearance. They're chiseled out of the host rock and I've never seen one in nodular form. But anything's possible.
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Post by MsAli on Oct 21, 2017 15:32:14 GMT -5
I've been cutting, selling, studying and learning about opal for well over 50 years and there's nothing about those nodules that says "opal" to me. But I learn something new about that amazing gemstone nearly every day so if you want my opinion I'd say slice them in half and see what's inside. You might be delighted or disappointed. The majority of Yowahs, for instance, are duds: ironstone all the way through. But some have nice opal displays and a tiny percentage have awesome opal interiors. There's little indication from the exterior either way. I've cut lots of Mexican opals and there's nothing about your stones that indicates Mexican origin in my opinion. The "Quarry" opals (Canteras) are the Mexican corollary to Australian ironstone or "boulder" opals and they have an entirely different appearance. They're chiseled out of the host rock and I've never seen one in nodular form. But anything's possible. I was talking to my ex and apparently he had little pieces of one
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Post by MsAli on Oct 21, 2017 15:41:34 GMT -5
I've been cutting, selling, studying and learning about opal for well over 50 years and there's nothing about those nodules that says "opal" to me. But I learn something new about that amazing gemstone nearly every day so if you want my opinion I'd say slice them in half and see what's inside. You might be delighted or disappointed. The majority of Yowahs, for instance, are duds: ironstone all the way through. But some have nice opal displays and a tiny percentage have awesome opal interiors. There's little indication from the exterior either way. I've cut lots of Mexican opals and there's nothing about your stones that indicates Mexican origin in my opinion. The "Quarry" opals (Canteras) are the Mexican corollary to Australian ironstone or "boulder" opals and they have an entirely different appearance. They're chiseled out of the host rock and I've never seen one in nodular form. But anything's possible. I was talking to my ex and apparently he had little pieces of one Tried to get better pictures
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gemfeller
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Opal
Oct 21, 2017 15:54:19 GMT -5
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Post by gemfeller on Oct 21, 2017 15:54:19 GMT -5
Yes, that looks like ironstone boulder opal from Oz -- most likely from the Koroit area but other mines produce somewhat similar stuff. There could be some nice cabs in that rough.
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Post by MsAli on Oct 21, 2017 15:59:34 GMT -5
Yes, that looks like ironstone boulder opal from Oz -- most likely from the Koroit area but other mines produce somewhat similar stuff. There could be some nice cabs in that rough. It would seem like a lot of work to get anything out of it if it all looks like these pieces.
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Post by beefjello on Oct 21, 2017 16:19:21 GMT -5
This thread made me think of a piece I picked up a few years back.. I'm assuming Koroit or Yowah? Any thoughts Rick? Oh and hi Ali!
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gemfeller
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Opal
Oct 21, 2017 19:04:32 GMT -5
Post by gemfeller on Oct 21, 2017 19:04:32 GMT -5
Yes, that looks like ironstone boulder opal from Oz -- most likely from the Koroit area but other mines produce somewhat similar stuff. There could be some nice cabs in that rough. It would seem like a lot of work to get anything out of it if it all looks like these pieces. You cut it with the ironstone as the base. Orienting it for best face-up show can be a pain but it can cut amazing cabs. Here's a (poor) example:
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gemfeller
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Post by gemfeller on Oct 21, 2017 19:16:16 GMT -5
beefjello , I really don't know. It's obviously ironstone opal but to determine the exact source you'd have to ask the miner. The ironstone opal deposits cover a wide area of Queensland and the individual mines seem to produce unique forms. The best boulder opals are considered equal to fine black opals and are graded/priced much the same way. But they're usually plates of full-spectrum opal on near-black ironstone bases. They can be spectacular, as can some of the best Yowahs like this one:
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Post by MsAli on Oct 21, 2017 19:21:21 GMT -5
It would seem like a lot of work to get anything out of it if it all looks like these pieces. You cut it with the ironstone as the base. Orienting it for best face-up show can be a pain but it can cut amazing cabs. Here's a (poor) example: So do you cut it open to see whats inside or just start polishing it down?
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Opal
Oct 21, 2017 19:27:14 GMT -5
Post by fernwood on Oct 21, 2017 19:27:14 GMT -5
I see lots of potential, based on the pieces pictured.
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Post by hummingbirdstones on Oct 21, 2017 19:37:13 GMT -5
Hi Ali!
Those nodules are most definitely Koroit boulder opal. I have seen them before and usually the opal is a dark/electric blue with concentric patterns inside if they are oriented correctly.
We used to call these dog poop boulder on the Opal Auctions forums because of the shapes.
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Post by MsAli on Oct 21, 2017 19:37:54 GMT -5
Hi Ali! Those nodules are most definitely Koroit boulder opal. I have seen them before and usually the opal is a dark/electric blue with concentric patterns inside if they are oriented correctly. We used to call these dog poop boulder on the Opal Auctions forums because of the shapes. Lmfao they do resemble that
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gemfeller
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Post by gemfeller on Oct 21, 2017 20:17:12 GMT -5
hummingbirdstones, I was trying to be discreet, LOL. Maybe "faux canine coprolites?" Thanks for the ID. I've cut quite a bit of Koroit but have never seen that form.
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gemfeller
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Opal
Oct 21, 2017 20:30:51 GMT -5
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Post by gemfeller on Oct 21, 2017 20:30:51 GMT -5
MsAli , I try to "sneak up" on 'em. My advice is to grind a little and look a lot, as the faceters say. The two key things I think are keeping the best color on the face of the stone while making sure there's a solid base of matrix to form a cab from. It can involve quite a bit of exploratory grinding and sawing before the final shape and size are chosen. Maybe hummingbirdstones can offer more specific advice for this type of Koroit since she's cut it. I cut a couple of lower-grade Koroit cabs this afternoon and was reminded that while the ironstone itself is solid and takes a fantastic polish, there are sometimes soft spots that undercut like crazy. You just have to proceed carefully and be aware that such problems can occur.
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Post by MsAli on Oct 21, 2017 20:36:58 GMT -5
MsAli , I try to "sneak up" on 'em. My advice is to grind a little and look a lot, as the faceters say. The two key things I think are keeping the best color on the face of the stone while making sure there's a solid base of matrix to form a cab from. It can involve quite a bit of exploratory grinding and sawing before the final shape and size are chosen. Maybe hummingbirdstones can offer more specific advice for this type of Koroit since she's cut it. I cut a couple of lower-grade Koroit cabs this afternoon and was reminded that while the ironstone itself is solid and takes a fantastic polish, there are sometimes soft spots that undercut like crazy. You just have to proceed carefully and be aware that such problems can occur. Thank you. Now I just have to find someone to cut em for me
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zarguy
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Member since December 2005
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Opal
Oct 21, 2017 21:35:11 GMT -5
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Post by zarguy on Oct 21, 2017 21:35:11 GMT -5
I acquired a partial "nut" that was already cut open that looked very similar to yours. Smooth exterior. The inside has concentric flashes of green, blue & purple. You should seek someone who's experienced at cutting. You don't want to waste good material on an amateur. Lynn
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Opal
Oct 22, 2017 11:49:36 GMT -5
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Post by hummingbirdstones on Oct 22, 2017 11:49:36 GMT -5
hummingbirdstones , I was trying to be discreet, LOL. Maybe "faux canine coprolites?" Thanks for the ID. I've cut quite a bit of Koroit but have never seen that form. gemfeller, I WAS being disceet! I have never actually cut a piece of that type of Koroit. It is extremely hard to come by and when I first saw it on Opal Auctions (maybe 2006 or 2007) the few parcels I could find were crazy expensive, even back then. Now I'm on a mission to find some again. I did spend a couple of hours last night on the Way Back Machine, trying to find the thread that discussed it, but wasn't successful. Since the forums there are defunct, it's the only way to access any of that information. Too bad, really. I did get a little distracted reminiscing over some of those old threads. I would think it would be pretty straight forward boulder cutting. You would just need to determine which the directions the slices should be cut to get the circular patterns. I would guess slicing across the nodular parts would do it. Skinning the outside down to where the opal starts to show would be an easy way to know for sure.
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