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Post by toiv0 on Apr 1, 2016 18:15:39 GMT -5
Looks like unakite in matrix? Only thing is doesn't really have the granite look to it. Kind of green, pink and quartz, Matrix is black. Couldn't get a picture of the out side to download for some reason.
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Post by toiv0 on Apr 1, 2016 18:16:29 GMT -5
This stone is about 6 inches x 4 inches
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droseraguy
Cave Dweller
Member since April 2012
Posts: 426
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Post by droseraguy on Apr 1, 2016 20:41:36 GMT -5
Just a guess but might be some kind of tillite. The similar nature of the stones though makes me think not. Where did you find it ?
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Post by Peruano on Apr 1, 2016 20:56:52 GMT -5
I think its fairly safe to call it a pegmatite. Extremely large crystals of volcanic origin, matrix is often a black substance of magma origin and may be a type of gabbro. Big crystal, black matrix are the clues. Tom
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Post by Jugglerguy on Apr 2, 2016 6:58:13 GMT -5
I'm up in the U.P., and I don't have my rock books with me, but that's in the book. It's fairly common in Michigan.
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Post by toiv0 on Apr 2, 2016 7:27:37 GMT -5
Just a guess but might be some kind of tillite. The similar nature of the stones though makes me think not. Where did you find it ? This was found in Northern MN south of the iron range, nw of Duluth. I haven't found any pudding stones up here ever. Sometimes agates in matrix or Thomsonite.
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Fossilman
Cave Dweller
Member since January 2009
Posts: 20,711
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Post by Fossilman on Apr 2, 2016 14:51:27 GMT -5
Whatever it is,I like it!!!
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Post by Jugglerguy on Apr 2, 2016 16:44:56 GMT -5
Pudding stones are conglomerates, so I don't think your rock would be considered a pudding stone. My book is called "Lake Superior Rock Picker's Guide" and lists it as "Probably metamorphosed basalt porphyry. I had one that looked exactly like yours, but I think I ended up throwing it back. If you make a cab and it turns out, let me know so I can feel bad about throwing it back
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Post by toiv0 on Apr 2, 2016 18:04:47 GMT -5
I think you nailed it, thanks.
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