NevadaBill
fully equipped rock polisher
Member since January 2019
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Post by NevadaBill on Mar 18, 2019 10:26:03 GMT -5
I think that these four rocks might be of the same family. At least 2 of them. But perhaps they all share similar make up. All four were found, alone, not accompanying any others which looked like them, in four different places within a mile or two of each other. They were found on all sides of a larger desert hill, covered with all forms of extrusive volcanic rocks. Here is a group photo. They are all very sparkly. My wife likes them and wanted to know what they are generally called. Here is two of them. This one has a slightly tighter formation of the shiny surface. This last one has a different color, but it kind of the same thing. Again, found by itself, stuck to a spire of mud, suspended several inches above the ground. I guess I were to take a magnifying glass to these, the surfaces would be formed by a bunch of little squares and cubes, shiny, all jammed together. I'm not tumbling them, but it would be cool to know what they might be made of. They are kind of sparkly when brought to the light. Maybe a short video will help:
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Deleted
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Post by Deleted on Mar 18, 2019 11:11:13 GMT -5
First thing that came to my mind, especially the greenish one, was something containing biotite.
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NevadaBill
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Post by NevadaBill on Mar 18, 2019 19:18:44 GMT -5
Could be. Very interesting. I don't know.
I do know that they are worthless, and common. I actually saw 3 of the 4 varieties (they are all a bit different) today during a field trip. And one additional one which I almost brought home, which was Green with Golden sparkling speckles. I saw it early and didn't feel like carrying it around.
I just wouldn't mind knowing what this worthless Igneous Volcanic rock is. I will look up Biotite now.
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fuss
spending too much on rocks
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Post by fuss on Mar 19, 2019 10:21:59 GMT -5
You could do a few tests to confirm, but they look like mica schist rocks with biotite and or Muscovite mica like rocks2dust said.
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lookatthat
Cave Dweller
Whatever there is to be found.
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Post by lookatthat on Mar 19, 2019 14:23:25 GMT -5
If they are flaky, fairly soft and crumbly, they could be biotite. Under magnification if you can see little "books" of crystals, that would be telling of a kind of mica.
if they are heavy, dense, and quite hard, they could be hornblend or contain hornblend.
They look like a kind of mica schist, to me, from here.
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Sabre52
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Me and my gal, Rosie
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Post by Sabre52 on Mar 19, 2019 15:38:03 GMT -5
Hope I'm spelling this correctly: micaceous shist....Mel
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RWA3006
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Post by RWA3006 on Mar 19, 2019 20:49:30 GMT -5
Shist, mica. We have tons of it nearby here in Farmington canyon where gneiss is abundant. I see it constantly and your photos are a dead match.
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NevadaBill
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Post by NevadaBill on Mar 20, 2019 10:34:13 GMT -5
You could do a few tests to confirm, but they look like mica schist rocks with biotite and or Muscovite mica like rocks2dust said. I think that we have a winner here. Mica Schist is a match. So is Biotite in some cases. Thanks for saving me hours of searching around on the internet. It is so common that I was seeing small samples of it in my landscape rock yesterday.
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NevadaBill
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Post by NevadaBill on Mar 20, 2019 10:43:39 GMT -5
OK, these are pretty obviously "Micaceous Schist". Thanks for the more scientific name Mel!
If figured it would be real easy for someone that had a Geology background.
Randy, it is odd you mention "... Farmington canyon where gneiss is abundant". In all cases this stuff was found next to Gneiss. Maybe there is a connection between the Gneiss and the Mica Schist.
I wish I went to earth school when I was little.
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RWA3006
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Post by RWA3006 on Mar 20, 2019 17:00:11 GMT -5
OK, these are pretty obviously "Micaceous Schist". Thanks for the more scientific name Mel! If figured it would be real easy for someone that had a Geology background. Randy, it is odd you mention "... Farmington canyon where gneiss is abundant". In all cases this stuff was found next to Gneiss. Maybe there is a connection between the Gneiss and the Mica Schist. I wish I went to earth school when I was little. There's certainly a connection here in this location. Farmington canyon is a classic location where one can observe many alternating layers of these materials in tortured bands that have been severely folded in the mountain side. Quite beautiful to look at.
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