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 Post subject: Re: Buying online: a crapshoot
PostPosted: Wed Sep 04, 2013 3:15 pm 
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Nothing too atypical for Welo opal there, though it is (imo) a desireable feature.

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 Post subject: Re: Buying online: a crapshoot
PostPosted: Thu Sep 05, 2013 12:48 pm 
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Yeah, I was looking at the host rock in the back which is why I said it MAY be too shallow for faceting. Hard to tell.

I agree with Scarodactyl on your opal, looks like a nice piece to me. I have seen some truly bizarre Ethiopian opals, you can get all types of odd looking color play that are hard to believe are natural.

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 Post subject: Re: Buying online: a crapshoot
PostPosted: Sun Sep 08, 2013 1:26 am 
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Question about opals:
Does even the smallest crack, even internal, mean it's useless?

I've read on some of the pages the lapidary I use's website that certain inclusions can be cut around. If you find any crack, can an opal be saved?

Here's what I mean. I can only see this with a very high powered light:

The crack's on the right. It's not to the surface, and light doesn't reflect off of it like it does the standard play of color it just casts a shadow.

The opal seems to permeate the stone from that front to the back:


I know the crack is something that will affect the cutting of the stone, but will it affect the stability? Are all cracks signs of the whole stone's instability?

Here's a video of the opal:


Edit: Here's a few more images by me. I suck at taking these compared to the seller.


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 Post subject: Re: Buying online: a crapshoot
PostPosted: Mon Sep 09, 2013 1:03 pm 
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Tough question, but in general opal is different from other materials in that you really don't want to leave any inclusions in the final stone. Especially with hydrophane opals any cracks are likely to grow and cause one stone to become two at some point.

What I do is soak the opal in a glass of water for a day or so, then leave it out to dry for another day, then pull the stone apart along any fractures. After that wahtever chunks I have are very likely to survive cutting in one piece.

Also, sometimes there are internal structures that look like cracks but are just density gradients or healed fractures. If you soak it and it doesn't split, it might not really be an inclusion/crack.

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 Post subject: Re: Buying online: a crapshoot
PostPosted: Mon Sep 09, 2013 2:29 pm 
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I would think that a crack like that one (single, straight crack, through and through) wouldn't be as indicative of instability as curved cracks on the surface would be, but that is based on intuition rather than data. What bobsiv said sounds like a pretty reasonable test, anyway.

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 Post subject: Re: Buying online: a crapshoot
PostPosted: Mon Sep 09, 2013 3:48 pm 
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Scarodactyl wrote:
I would think that a crack like that one (single, straight crack, through and through) wouldn't be as indicative of instability as curved cracks on the surface would be, but that is based on intuition rather than data. What bobsiv said sounds like a pretty reasonable test, anyway.


Sent it off to the Lapidary,

I'll let him know that I haven't performed any stability tests on it and let him use his best judgment on it. He did mention that it coukd be the same things you two mentioned, a previous crack that healed by being filling in, a density variation, or a darker material filled just happens to be there.


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 Post subject: Re: Buying online: a crapshoot
PostPosted: Tue Sep 17, 2013 2:39 pm 
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I've attached an image the Lapidary gave me. He's cut off the outer shell and the dark mark I saw was definitely a crack. He sent the image I've included below. He's cutting it into two stones, the matrix goes into the back quite a ways, so it'll lose some of its weight. After removing the mud shell the remaining rough weighs 6 grams, or 30 carats.



I think he's illuminating the stone from the back to show the crack, otherwise, the remaining fire is ... not very nice.


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 Post subject: Re: Buying online: a crapshoot
PostPosted: Tue Sep 17, 2013 2:44 pm 
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For a heavily frosted surface and non-optimal lighting/non-focused picture, the fire is actually showing pretty darned well IMO. Too bad it's lost weight, but I'm excited to see the final product(s).

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 Post subject: Re: Buying online: a crapshoot
PostPosted: Fri Sep 20, 2013 7:57 pm 
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Here's the image from the lapidary:
Image


Should I have him back these or is there sufficient body tone to avoid that?


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 Post subject: Re: Buying online: a crapshoot
PostPosted: Fri Sep 20, 2013 10:07 pm 
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Have him send you a photo on a white background. What you're seeing with a black background is what they would look like as a black-based doublet. I've got one like that, looks fabulous against black, looks like nothing against white.


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 Post subject: Re: Buying online: a crapshoot
PostPosted: Sun Sep 22, 2013 12:10 am 
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Julie Gowans-Poli wrote:
Have him send you a photo on a white background. What you're seeing with a black background is what they would look like as a black-based doublet. I've got one like that, looks fabulous against black, looks like nothing against white.


I suggested it, but he replied that he will just send them to me as he doesn't make a whole lot off of smaller projects.


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 Post subject: Re: Buying online: a crapshoot
PostPosted: Mon Sep 23, 2013 4:27 pm 
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A trick you can use is to put a bit of black epoxy on the backs. If you don't have black epoxy, you can mix a bit of black powder pigment from an art shop into regular epoxy and it works a trick.

I've done this mounting some light/translucent opals and it's enhanced their flash considerably. Of course you should disclose this if you're selling them.

Hope this helps

-Allan

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 Post subject: Re: Buying online: a crapshoot
PostPosted: Mon Sep 23, 2013 10:51 pm 
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Or if you intend to sell them mounted, have the back of the bezel setting black rhodium plated. Obviously, also to be disclosed...


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 Post subject: Re: Buying online: a crapshoot
PostPosted: Mon Sep 23, 2013 11:35 pm 
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Generally I would worry about putting a backing on them since it isn't a typical thing done to ethiopian stones. It might be accepted with Australian stones (and others like Spencer, Idaho) but I have a feeling that people would tend to look askance at wello opals with backings.

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 Post subject: Re: Buying online: a crapshoot
PostPosted: Wed Oct 01, 2014 5:59 pm 
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Image Image

Image Image

Image Image

Image Image

Image


Above is photos of an opal I bought in April. 248.3ct.

I waited until now to send it out due to various reasons, but in other news: it yielded pretty well, Monday or Tuesday of next week I should receive a 113ct opal and a 25 ct opal from the Lapidary.

I'll post back with more images then. Is 55% yield decent?


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