🔎 UNIDENTIFIED Green sedimentary with some flecks (feldspar?)

[Blackfoot58]

I see these green rocks mixed in with our quarried gravel. I put this one in the tumbler for one day. It can be scratched with a knife blade, but not easily. I’d guess Mohs 5.0 - 5.5.
May have feldspar or pyrite flecks throughout. Looks to have a layered appearance which I’d guess to be sedimentary. I know it isn’t rare (on Iowa gravel roads) but is different from standard quarry gravel. A friend suggested gneiss, but I thought I’d use the forums. Thanks.
This picture was “wet”

Dry picture

 

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[ToddsPoint]

If it contains feldspar it’s not a sedimentary rock. Only igneous and metamorphic rocks have that. It looks a bit like Amazonite but it’s kind of dark for that. So many rocks, so little time!

 

[Blackfoot58]

If it contains feldspar it’s not a sedimentary rock. Only igneous and metamorphic rocks have that. It looks a bit like Amazonite but it’s kind of dark for that. So many rocks, so little time!View attachment 2166114

Thanks. The flecks appear to be pyrite on closer examination. Very small and gold in color.
I’m probably crazy, but I’m going to pick up a small batch and tumble them for a full 4-step cycle. Just to see what the results will be.

 

[Bucket Lister]

I’m probably crazy, but I’m going to pick up a small batch and tumble them for a full 4-step cycle. Just to see what the results will be.

Isn't that what rock tumbling is all about? 😁

A little softer (at 4) I was thinking possibly fluorite.

 

[Blackfoot58]

I’ve been reading about a sandstone/glauconite mix.
The glauconite has a low Mohs hardness and the sandstone can be fairly high. I’m not certain as to how it would score with the knife blade scratch test. Kinda grasping at the proverbial straw.