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 Post subject: How to determine what this stone is
PostPosted: Wed May 06, 2015 6:54 pm 
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This is a real beginners only question, but i'm not afraid to ask dumb questions if the answers make me less dumb :) .

I have a piece of jewelery with a blue stone in it. I like the stone it's got a real cool pattern to it, but it came from a box of junk so it is very dubious. The quality of the setting seems at least to my untrained eye to be nice, but it is not marked anywhere. Anyways it caused me to read your optical properties of gemstones article and wow that it so detailed it answered so many questions i had kicking around since i started looking at this thing. But it brought a really interesting question to mind: I haven't seen an agate this deep a blue color or with this same type of relflection, but hey i haven't seen a million agates, i just collect rocks. So assuming it's not an agate or something caused by an aggregate process how would this banding even occcur? Is it some sort of impurity that formed in a circular pattern or is this an artifact of an unnatural manufacturing process. It just doesn't seem to me that you would manufacture something to have these imperfections that most people would say makes it not super clear or of a pure color. I have read many posts on this forum and you guys really know what you're talking about and most importantly explain your thought processes to help others like me who are ignorant learn something. These are a few pictures of it. I paid nothing for it and am not worried so much about it being real, but just what can we do (besides like instrumented analytical tests i don't have access to) to make such determinations. If you can help me I would be so happy.
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 Post subject: Re: How to determine what this stone is
PostPosted: Thu May 07, 2015 7:11 am 
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For my eye it is just dyed agate... But... There is some "But"... I know (I have) chalcedony with no treatment with same color.. Why should not be agate of such a color exist? At least there is a chance. Otherwise with no testing question can not be answered..

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 Post subject: Re: How to determine what this stone is
PostPosted: Thu May 07, 2015 10:43 am 
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For me it's man-made glass.
The surface seems to be damaged.
And it looks like it has been glued to the setting.


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 Post subject: Re: How to determine what this stone is
PostPosted: Thu May 07, 2015 2:42 pm 
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I should really take a stab at scratching it and see what happens, I should have done that first but I got caught up in thinking whether or not that pattern could be something natural. I really didn't think it was an agate because when I look at it it seems more like light actually penetrates it to some degree. Again i haven't seen every agate in the world but with the ones I have seen at least in rock shops they are glossy on the surface just because they are polished so heavily. The appearance is a little different to me but not in any way i can objectively describe.

Glass seems like it could be a better answer but if someone made something fake out of glass wouldn't they just make it a flawless blue and pass it off as some kind of mock sapphire? Either that would be impossible or more people have an appreciation of stones with patterns than I imagined :) Unless it was not ever meant to decieve but just to be an artistic piece of glass :idea: I have seen a lot of cobalt blue glass in my days of collecting bottles though and that color does in places almost seem to approach the colors I have seen in them, but I have never in person seen a pattern in cobalt blue glass.

I tried something new on it. I hit it with a UV light. I don't know if it is long wave UV or short, but it has a large bank of UV leds (a very fun toy too). The thing kinda glowed it was cool, I will look into that more later. I couldn't hold onto the stone and the camera at the same time to get a good picture.

I don't know if it's glued in or that metal is crimped toward the bottom or what, i will check that out. If it's glued I guess there's no harm in pulling it off, so i will. Here is a picture of the front and one of the back if that is helpful. I know the discussion is about the stone, but if the style gives any clues to age maybe it could lend a clue as well to what kind of stones, fakes, or even just artistic glass were popular at the time or in that style of setting.

Again, thanks for helping. This is a learning experience for me. I am really trying to figure what I can do with just my eye and a loupe to determine at least if something deserves further study. I never buy jewelry, I only ever buy rocks as specimens to put on a shelf. That's the angle i'm coming from. I have never had to consider something being fake because if you buy a cool garnet sticking out of schist no one would bother faking that.

Here is what the whole thing looks like:
Attachment:
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20150501_132015.jpg [ 91 KiB | Viewed 1374 times ]
Attachment:
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20150501_132049.jpg [ 56.98 KiB | Viewed 1374 times ]


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 Post subject: Re: How to determine what this stone is
PostPosted: Fri May 08, 2015 1:14 pm 
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Just by looking at the stone I would say that the stone is man made glass.

The swirl lines are typical of glass.

The fracture is typical of glass,

The surface appears to be crazed, which is an indicator that it is molded.

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 Post subject: Re: How to determine what this stone is
PostPosted: Fri May 08, 2015 1:50 pm 
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Touch it with your tongue.


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 Post subject: Re: How to determine what this stone is
PostPosted: Fri May 08, 2015 4:17 pm 
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Thanks guys, i was thinking last night maybe they made it the same way they make glass marbles with swirls on them. Is touching it with my tongue a joke or will that show me something? I'm not at all beyond doing that (i just did it as a matter of fact). It only felt smooth. I really only ever licked stones that i pulled from the ground so i have no frame of reference as to what I would be feeling for. If i was a joke that was mean :roll:


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 Post subject: Re: How to determine what this stone is
PostPosted: Fri May 08, 2015 5:21 pm 
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lesliekinder wrote:
Just by looking at the stone I would say that the stone is man made glass.

The swirl lines are typical of glass.

The fracture is typical of glass,

The surface appears to be crazed, which is an indicator that it is molded.


And I was going to guess plastic.


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 Post subject: Re: How to determine what this stone is
PostPosted: Sat May 09, 2015 12:15 am 
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My 1st thought was glass.


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 Post subject: Re: How to determine what this stone is
PostPosted: Sat May 09, 2015 12:41 am 
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And here I half expected it to be made of wood.

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 Post subject: Re: How to determine what this stone is
PostPosted: Sat May 09, 2015 1:31 am 
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thanks guys i'll take it to be glass. i guess that's why it didn't make sense to be a stone. that's all from me. I will ask no more


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 Post subject: Re: How to determine what this stone is
PostPosted: Thu May 14, 2015 12:39 am 
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Seeing the first image I thought it is a liquid. The second image looks like a glass


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 Post subject: Re: How to determine what this stone is
PostPosted: Mon Aug 10, 2015 3:16 am 
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yeah, really a perfect one for any beginner. before start everyone wants to know how can they know the quality of any stone.


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