gemfeller
Cave Dweller
Member since June 2011
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Post by gemfeller on Dec 30, 2013 22:31:04 GMT -5
If you've polished the vein material it might be possible to get a refractive index reading. That could narrow the possibilities down a lot. So would a spectroscope test if one could get enough light through it. But pictures on-line aren't going to ID it. You're highly unlikely to find a schist with vein material exactly like it. Rick Thanks for the insight. I can't find a pic online of a single Mica Schist with a vein of any size or type. Radio, without specific location info or data from optical and other tests, ID-ing your specimen is like looking for a black cat in a lightless coal mine. Contact metamorphic zones where hot igneous rock melts and transforms adjacent rocks are delicious soups of whatever minerals may already exist in the host rocks. They recombine, crystallize and form veins consisting of almost anything, and garnets of some kind are common. But garnets are associated with specific elements: iron, chromium, manganese, magnesium, calcium, vanadium, aluminum, titanium and silicon. Worse from the ID standpoint, garnet species are miscible, meaning they can combine with one another. There are almost infinite possibilities for those combinations. Enjoy your specimen and good luck with the ID. Rick
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Dec 30, 2013 23:11:29 GMT -5
Nice 'splanation Rick. We all thank you.
And therefore, names can only be an approximation without detailed laboratory analysis.
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Post by nowyo on Dec 30, 2013 23:47:50 GMT -5
Gemfeller, that's about the clearest, most concise description of what is going on with these metamorphic rocks that I have read. Pass that on to a few college professors, would you please?
Russ
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Post by radio on Dec 31, 2013 9:39:59 GMT -5
I really appreciate everyone's input on my fascinating rock! At least I know a lot more about it than I did thanks to you good folks on RTH If we knew all the answers and the ID's of all the rocks, the hobby would loose it's fascination, no?
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Post by Peruano on Jan 1, 2014 8:57:23 GMT -5
Radio, You have received lots of good responses, and I can add only a bit more to the discourse. I hike and hound frequently along the west margin of the Manzano Mts in New Mexico. Nearly everything exposed that is not recent alluvium is Precambrian metamorphics and yes a wide array of schists including mica schists with granite intrusions. Could the crystal center be a vein of predominantly reddish feldspar? They are often folded like your specimen, often have larger blocky inclusions (hornblende, etc.) and some go further into the chlorite schist range. I'll try to dig out some photos and or would appreciate a better photo of your specimen. In short contact metamorphic garnet schist with other things showing through as well would be my best guess. Tom
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