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Post by snowmom on Jun 16, 2014 10:02:16 GMT -5
found a lot of cool stones this weekend on lake Huron beaches, among them : a piece of tiger eye and some mixed brecchiated jaspers, conglomerates and oolitic stuff, even a small piece of lake smoothed pet. wood. This one has me a bit surprised though.
The black seems to be overlaid over the gold ( not metallic?) and you can see swirls and small bits of other colors showing through it in places. Must be some sort of jasper/chalcedony/agate... but what? This would have come down to MI with Canadian shield material and the glaciers. Anybody recognize it as a known form from Canada ?
It shocked me when I saw the last photo and it seemed a bit chatoyant. very mysterious!
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panamark
fully equipped rock polisher
Member since September 2012
Posts: 1,343
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Post by panamark on Jun 16, 2014 10:33:58 GMT -5
Can you post a picture of the tiger eye? It would be very surprising to me to find tiger eye in Lake Huron.
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Post by manofglass on Jun 16, 2014 10:54:40 GMT -5
What you need is a tumbler it will clean the rock up to better see what you have
Walt
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Post by snowmom on Jun 16, 2014 11:08:02 GMT -5
Perhaps it goes by another name, it seems to have asbestos (broken end shows fibers running 2 ways with a little calcium coating from being in the lake so long)look at the end on the right side of the photo. Chrysotile is common here and so is iron banded stuff, all brought down from Canada by the glaciers. It is not mined here, and only found in places deposited by glaciers in random ways. It is lake worn. I can download more photos if you'd like to see more.
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Post by snowmom on Jun 16, 2014 11:55:30 GMT -5
yea or nay?
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Post by snowmom on Jun 16, 2014 11:56:48 GMT -5
manofglass, walt, I'm working on it! : )
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Post by rockjunquie on Jun 16, 2014 14:03:50 GMT -5
Very curious.... I like the first one- reminds me of bat cave jasper (or cave rim or something like that) and the second really does look tiger eye'ish.
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Post by snowmom on Jun 16, 2014 15:39:57 GMT -5
I'm curious too. I want to learn! I am learning the geology of this area, and have found that everything I pull out of the lake except limestone and fossils was brought here by the glaciers from the eastern UP and Canada. I find an incredible variety of interesting stuff, its just that none of it is indigenous, it is all 'imported', and almost all of it is pre-smoothed by glaciers and worked on by water/sand for centuries. I'd say for sure it is asbestos impregnated with something or other (the tiger eye one) you can see the fibers in my 10x magnifying glass, some visible with bare eye. Anxious to hear what everybody has to say about both of these!
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Post by snowmom on Jun 16, 2014 21:10:48 GMT -5
Spent a good bit of time searching tiger eye this afternoon. This can't be tiger eye because real tiger eye is a replacement stone, with quartz replacing the asbestos fibers. In this stone there is still asbestos visible, so it is a serpentine or chrysotile of some sort, a tigers eye "work in progress" or young tiger eye...not 'the real thing' appearances to the contrary. Thanks for raising the question Panamark. still haven't figured out what is going on with the black agate thing in the first pictures...
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Post by snowmom on Jun 17, 2014 5:36:51 GMT -5
no, wait, if the fibers are replaced with quartz, it still looks fibrous, doesn't it? I notice there is a bit of reddish (not blue)cast to the light reflected from it. I give up!
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panamark
fully equipped rock polisher
Member since September 2012
Posts: 1,343
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Post by panamark on Jun 17, 2014 10:15:30 GMT -5
One thing about tiger eye is that the fibers run perpendicular to the band of tiger eye. For example if the stone has a 1/2" wide band running horizontally 3" through the stone, the tiger eye's silicified fibers will run up and down the 1/2" length not laterally the 3" length. I.e. the chantoyant fibers always run the short length, even though there may be colored stripe the long length. Does this make sense?
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Post by snowmom on Jun 17, 2014 17:34:04 GMT -5
yep, it does make sense, and it has that, that's why I said it ran both ways. oy this is confusing. some days I despair of ever getting it all straight. loving the learning though. thanks Mark!
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