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Post by sbreed on Sept 9, 2009 21:48:31 GMT -5
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Post by rhodescabbin on Sept 9, 2009 22:11:14 GMT -5
That sure reminds me of a rock from Iceland, I'm thinking its called Iceland Feldspar??? Whatever it is, sure is interesting... Update: I was thinking of Iceland Spar which is a clear variety of calcite. I have some that looks like sheets of ice and it comes in a block type shape also kind of like moonstone: www.mindat.org/gallery.php?min=4900After looking at the pics from the above link I believe Mel's findings are more accurate...
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,487
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Post by Sabre52 on Sept 9, 2009 22:30:57 GMT -5
Looks like aragonite to me. I was going to say a cone in cone type development but those are usually more fibrous and less squared off. It looks more like a series of aragonite phantom crystals layered one on top the other with the color change being due to impurities in the layers. Several other minerals do this to ie. fluorite. If it's a hard specimen rather than soft it might be a phantom quartz crystal as the cross section does look to be six sided. If soft, probably aragonite (similar in chemical composition to calcite) phantom as I think I remember they can be six sided too..Mel
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Post by tkrueger3 on Sept 9, 2009 22:49:58 GMT -5
My uneducated guess would be that it's a broken part of what was once a huge, extremely complex, 3-dimensional intarsia. That, or the nose off of some ancient Aztec fertility god! LOL!
It's for sure an interesting piece, isn't it? I thought you never found straight lines or 90-degree angles in nature, but hey - there they are!
Tom
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brent
fully equipped rock polisher
Member since November 2008
Posts: 1,316
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Post by brent on Sept 10, 2009 8:34:05 GMT -5
It looks really cool. A good piece to put on display and have people pull there hair out trying to figure out what it is...lol.
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Post by johnjsgems on Sept 10, 2009 11:37:33 GMT -5
I'd drop a drop of acid somewhere unobtrusive and test for calcite. Tom, straight lines occur on most crystaline structures
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Post by sbreed on Sept 11, 2009 12:24:51 GMT -5
I did a scratch test........it scratched with a nail. Does that mean it is aragonite? I had to push a little to get it to scratch.
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karenfh
fully equipped rock polisher
Member since November 2006
Posts: 1,495
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Post by karenfh on Sept 12, 2009 1:19:01 GMT -5
Very cool, no matter what it is.
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Post by sbreed on Sept 13, 2009 8:55:04 GMT -5
I can't find anything that looks like that under aragonite.
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