Creek walking today: some misc. jasper & chert

[Blackfoot58]

Looking for tumbling rough. Found misc jasper. Bottom row: agatized jasper. 2nd row, right: banded jasper.
Some are really small, but I keep them for the grandkids. They like them.
The black rock is around 7 Mohs. Waxy look, no visible crystals. I’m guessing black chert. If so, it’s the largest chunk I’ve found.

 

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[ToddsPoint]

Your black rock is igneous, not flint. It looks like basalt to me. Put a billet on it and see if you can detach a flake. Betcha can’t!

 

[Blackfoot58]

Your black rock is igneous, not flint. It looks like basalt to me. Put a billet on it and see if you can detach a flake. Betcha can’t!

I’ll try that. Thanks

 

[Blackfoot58]

Your black rock is igneous, not flint. It looks like basalt to me. Put a billet on it and see if you can detach a flake. Betcha can’t!

It split with one billet strike. Perfectly flat cleavage. Definitely not flint/chert.

 

[ToddsPoint]

It split with one billet strike. Perfectly flat cleavage. Definitely not flint/chert.View attachment 2170119

If it split that easy and cleanly it must have been sedimentary to start with. And then metamorphic?? Shale and slate split like that. Igneous rocks seldom do.

 

[Blackfoot58]

If it split that easy and cleanly it must have been sedimentary to start with. And then metamorphic?? Shale and slate split like that. Igneous rocks seldom do.

If I look very closely, it has very thin layers. They are more obvious on one side than anywhere else. Very fine sedimentary pressure stacking.