What type of rock is this?

S

sintro

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A few years a man who worked in a mine somewhere here in SE Wisconsin gave me two of these stones after I had been eyeing them up for years. He said they find them constantly. It's kinda of like really reflective oatmeal sandwiched together. What is it? I thought it might be something like mica.

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Sorry if this isn't the correct area.
 
I cannot remember the proper name, but I think I remember something like "Fool's gold" being used.
 
Looks like some iron pyrite (fools gold) that I have. The piece that I have is a lot smaller.
 
Sorry to be like this.....but it is probably a mineral not a rock:)
It is difficult to tell from your pic and without holding it, but it appears to be mica or maybe muscovite (they are very similar). The easiest way to get a good ID would be to take it to a school and get a geology teacher to look at it. They will be glad to help!
 
I think you're on the right track - some sort of mica schist. I've seen samples where the structure is loose enough to scrape off with a fingernail, and some that would mar a blade. Cool rock.
 
Pyrite is the term you're looking for, but I don't believe that is what it is.
My guess would be Mica.
Mongo said:
I cannot remember the proper name, but I think I remember something like "Fool's gold" being used.
Click to expand...
 
I've seen fools gold and this is more silver, not gold at all.

^It really does look like muscovite after I looked at mica and muscovite pictures, it looks just likes this, but mainly just flecks of shiny against flecks of gray/black/silver. From what I just read is that muscovite is a variety of mica, is that true?
muscovite-schist.jpg


IMG_1035.JPG
 
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I believe its granite. I see those rocks all the time on the train tracks near my house. But im no rock expert, so i could be wrong
 
Your picture is out of focus, but if the shiny minerals are in very thin sheets there's a good chance you have some sort of rock with mica in it.

"Fools gold" is pyrite, and would be gold-colored.
 
RobCamlin said:
Really reflective oatmeal sandwiched together. That's what it is.
Click to expand...

I'm pretty sure that's the exact phrase I used on my daily geological reports on the drill rigs. :D

Seems like some of the reports were simply layer after layer of "really reflective oatmeal sandwiched together" and "black rock that tastes funny." ;)
 
All of the iron pyrite I have seen, the fools gold is shaped in cubes, it is very hard and solid. When I was a kid there was a lot of it laying around in the Rocky Mountains West of Denver Colo., I collected buckets full! What kept me interested was that somewhere someone was offering a huge reward for a perfectly shaped cube. The odds of finding one are astronomical and I never knew who was offering the reward, and never found a perfect cube.
 
The picture ain't great but as others have stated, it tends to look like mica. Of course, a picture doesn't allow other factors that are needed for a solid determination -such as weight, reflection, actual colour, density, crystal structure,...- to come forward. If you really want to know what it is, take it to your local geology teacher so he can atleast hold it. Nice find ;-)
 
Plutonium P38... It goes in the space modulator! :D

Mica is lighter in weight than what you would expect from it's size.
 
muscovite mica = light colored mica
biotite = dark or black colored mica.
Calling it a mica schist sounds technically correct.

you should be able to use a needle or knife tip to pry the mica sheets apart. They exhibit perfect cleavage in one direction (not cleavage as we commonly know it :) but the property of breaking along certain preferred planes)
 
I love cleavage! LOL pyrite aka fools gold will not "cleave" in thin layers like mica-based...ah...stuff so what you have is at least partially mica I'd say
 
The prominent mineral in that speciman looks like muscovite, making it a metamorphc rock. Can't see enough detail to say much more,


Thunderhorse
 
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