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 Post subject: Please help identify these stones
PostPosted: Sun Jan 26, 2014 11:22 am 
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I have come across these stones and am wondering if these are precious or semi precious stones. I have no knowledge of gems, so any help would be appreciated. The clear stone is very hard and about 2 cm long.

Thanks Again for any ideas!

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 Post subject: Re: Please help identify these stones
PostPosted: Sun Jan 26, 2014 2:37 pm 
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My guesses:
rock crystal (colorless quartz)
carnelian/agate
carnelian
agate or waterworn quartz
agate

but these are complete guesses--while they are compatible with the images, so are a lot of other stones. For instance, that first picture could also depict danburite, phenacite, topaz (ok, that would be a stretch with the fracture but still), spodumene, petalite, or even glass. Or any other number of colorless minerals--you get my point though. It's *probably* colorless quartz, but you can't know for sure from a photo. Other data is needed.

As to value: if the first piece is quartz, at 2 cm in length, it'd be worth... maybe a dollar, if you're convincing. If it were something else it would be worth a bit more.
The agates aren't worth too much, maybe 1-3 dollars a pound. Still, if you had the center red carnelian cabbed you might get a very pretty stone, and it's more fun to take it from rough to cut than to just buy a stone without a story. You'd get, maybe not a valuable stone, but not a worthless or unattractive one either.

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 Post subject: Re: Please help identify these stones
PostPosted: Mon Jan 27, 2014 6:48 am 
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Ok, Thanks very much! I know that it is impossible to tell for sure what they could be by just a picture, but just wanted to know what possibilities there were. I had wondered if there was any possibility that it could be a Diamond, but I knew it would have been an odd shape foe one, although the surface looked similar to photos of rough Diamonds that I had seen. All of these stones were found in Mongolia, right near the Gobi desert. Thanks Again!


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 Post subject: Re: Please help identify these stones
PostPosted: Mon Jan 27, 2014 1:22 pm 
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Ah, now that's interesting. The Mongolian provenance could add a bit of value to the agates (if such they are, but I'm actually fairly confident in that identification). People like stones with stories, and if it's from an undeveloped deposit of agates there's always the off chance it will have some unexpected and interesting internal patterning. My estimate was based on what common Brazilian agate would go for (since the ones sold in bulk rarely have exciting things inside).

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 Post subject: Re: Please help identify these stones
PostPosted: Tue Jan 28, 2014 10:28 am 
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Thanks again! My in laws just picked these off the surface out there where they have a small farm. They got all diffrent kinds of stones, and as I have always been interested in them, they gave me a good little bunch. I am planning to go out there myself in the spring when the snow melts, and see what I can find myself. I have so may different kinds and i just have no Ideas what the might be, and some are quite interesting. Ill post a few more pics of other stones.

This one has purple/green/blue under a 3mm thick clear cover.
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This one looks like it has been cut, to me, but this is how they found it.

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This one has black and clear mixed in it.

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I also though this was interesting.

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 Post subject: Re: Please help identify these stones
PostPosted: Tue Jan 28, 2014 2:52 pm 
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My guess on the first one is... maybe fluorite? The surface texture and internal sparkles match a riverworn sample I have and the color combination you describe would be very typical. Finding a big chunk of fluorite out isn't super common, though not unheard of I suppose.
The next one looks like a crystal, maybe of very dark smoky quartz, but maybe of something more exciting--a few more photos from multiple angles would help some on this one. The next piece also looks like it could be quartz or possible something more interesting.
That last one is a very typical agate with some 'fortification' (those curved bands). What you see in the center is probably what's called 'botryoidal' agate. Agate is made of quartz, but rather than being a single large crystal it's made of lots of microscopic crystals interlocked with each other. So instead of forming nice sharp crystals it forms those distinctive rounded crystal aggregates. That said, other minerals can do that too, and it's sometimes possible for them to form in cavities within a rock like that, but it's likely more agate.
As a side note, the insides of that agate are a mixed bag. Those clear/colorless sugary bits in the middle are normal crystalline quartz which generally doesn't look as nice when cut, but the outer banded yellow areas could be very pretty, and good fortification adds another dimension of interest in a cut stone. So I'd say, while the stone itself may not be worth cutting, it suggests that there's a good chance your others will be. Incidentally, having a cabochon made is usually not super expensive, especially relative to having things faceted.

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 Post subject: Re: Please help identify these stones
PostPosted: Thu Jan 30, 2014 9:16 am 
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Thanks again so much I am learning a lot from what you have to say!
I took a few more pictures of that stone.

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This purple stone is larger than the others it is about 8cm across and 5 cm high, would this also be an agate?

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Here also is an interesting one, it looks almost like some type of coral on the inside, with molten stone on the outside?

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 Post subject: Re: Please help identify these stones
PostPosted: Thu Jan 30, 2014 2:38 pm 
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The plot thickens. I think that that first one is smoky quartz, though with an interesting tabular crystal form--from one angle it looked just a touch like axinite but I think the simpler answer is right in this case. The second one is pretty exciting--that looks like a textbook botryoidal fluorite, and a pretty darned nice specimen at that. I suppose it could be agate but my bet is fluorite. A simple scratch test would easily separate them (fluorite is hardness 4, agate is 6~7), but I wouldn't recommend it on such a nice specimen unless there's a damaged spot somewhere on the bottom. And I think that you're right on that last one--it looks rather like an agatized coral, and again a pretty nice specimen.
You've got quite a treasure trove of nice material here!

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 Post subject: Re: Please help identify these stones
PostPosted: Wed Feb 05, 2014 9:46 am 
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I went out to the area yesterday and looked around myself for the first time, it was getting late when we got there, but was able to pick up a few stones myself. The area is a dark colored hill, possibly, an old volcano?? There are these stones laying all over on it. It was quite interesting area even though I was able to only spend a short time there. Here is a pic of the stones.

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 Post subject: Re: Please help identify these stones
PostPosted: Wed Feb 05, 2014 12:57 pm 
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This sort of agate classically weathers out of vugs in basaltic lavas, so your guess of it being a former volcano is probably right on the money. I found some similar nodules in the field in New Mexico.

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