Rock on! Is this a classic rock or something else?

A:

Hi - Your address is Umatilla County .. is that where your wife found this lovely river rounded cobble??!! It appears to be a quartzite cobble.   

It could also be pure quartz but it has the look of quartzite. Very resistant to weathering. With the Ice Age floods, a variety of rocks not local to NE Oregon/SE Washington were deposited by the floods. On top of this, we see evidence of a huge Bonneville flood that came down the Snake River bringing all sorts of rocks. My bet is, this rock came from the east via one of the huge floods. I'm sure someone on campus in the geology department could add to the story. What a great find!!

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