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Post by Alice on Jul 1, 2005 15:30:58 GMT -5
these are rocks that we have here locally (I could walk away with bucket fulls after a 2 minute visit to the river). I just don't know what they are. I see quartz in all of them. the one on the bottom left has much finer quartz then the other 2  Close-up of the one on the right  the other 2  |
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jul 1, 2005 15:36:31 GMT -5
Hmmm... granite?... conglomerate?... metaconglomerate? Are they banded? Are they crumbly?
That grey one underneath them I can positively identify as cement! ;D
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Post by Alice on Jul 1, 2005 15:47:11 GMT -5
LOL, it's a driveway brick. No they aren't crumbly at all. They're quite solid, and take about 2 weeks of coarse to smooth out in a rotary. Yes, I have found some with bands. (there's some bands in the pink one on the bottom) We have lots of granite here too, but it doesn't look much like these rocks posted above.... unless it's a finer form of it. Here's the granite we have here    |
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phoenix1647
starting to spend too much on rocks
Member since March 2013
Posts: 186
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Post by phoenix1647 on Jul 1, 2005 15:57:31 GMT -5
ooooooooh...pretty..
Pho
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rollingstone
starting to spend too much on rocks
Member since July 2009
Posts: 236
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Post by rollingstone on Jul 1, 2005 15:57:48 GMT -5
Well, yes, they don't look anything like your granite (which is incredibly coarse-grained by the way). In the top rock in your bottom pic, it looks like there are individual rounded rocks embedded in a finer matrix, which gets me thinking conglomerate. Since you say it is very tough and not crumbly even in a tumbler, I'm thinking that the conglomerate was metamorhosed, making it metaconglomerate. The other rock in the bottom pic is a bit blurry, but it looks like it is layered, making me think maybe sandstone? If it isn't crumbly, perhaps it was metamorhosed into quartzite? But it looks like there are individual grains visible, which would be more typical of sandstone than quartzite. I dunno, I'm guessing.
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Post by Alice on Jul 1, 2005 16:14:57 GMT -5
rollingstone, sandstone makes sense... looking at it closely, it does look like compressed sand. Just not sure where the color comes from though. This rock is everywhere... and ranges in color, from beige, brown, red-ish brown, light pink and hot pink.
Pink and hot pink?... where on earth is there pink sand? Certainly not around here.
But the rock is tough though... harder then the other 2 rocks.
Yes, the other pinkish one has bits of quartz (rounded individual rocks)... so I guess I'll go with what you're saying... metaconglomerate.
now what about the other rock (First close-up)... granite? also a metaconglomerate?
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stefan
Cave Dweller 
Member since January 2005
Posts: 14,113
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Post by stefan on Jul 2, 2005 9:38:07 GMT -5
Might be some Gniess (pronounced nice) A metasomething or other granite like formation- Cool looking stuff! Oh and the pinks will come from iron oxides (especially bacterial action)
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