Rock or Cave deposit?

[USNFLYR]

Hello, I normally post my metal items on the metal detector forums. A friend found this in a Southwest Washington job site. He noticed it did not look like most river stones from normal yard clearing and digging that he did near the house. The Columbia River is within two miles. Mostly we see balsaltic or typical rounded stones that have been sculpted by years of water influence.

This one has pits. The rock seems to have 2 types that have congregated or amalgamated ? ....is that even a word?....either way it looks like two different rocky surfaces. The surface is smooth and sandy. It also has milky darker material. It is very heavy.....

Maybe from a a cave or cavern?

Any help?

 

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[Kray Gelder]

IMO, it's a hunk of quartz that formed in one of the pockets or voids inside the basalt, or pyroclastic flow, after it stopped flowing. The piece eventually eroded out of one of those basalt cliffs along the river, or any other volcanic deposit upstream from you. It still maintains most of it's original shape with some water tumbling, but not much. I don't think it spent much time in the river bed itself. Probably an old flood deposit.

 

[USNFLYR]

Thanks Kray!