identification help

Hello everyone, I discovered this awesome find in a dry river bed near Faribault Minnesota. I believe there are three possibilities for what this rock is. I believe it is either a large agate, banded jasper, or a banded iron formation. What else could this mystery rock be? I’m new to this...

Looking for opinions on this one! I’d say it’s a little greener In person than in the photos. It’s also slightly magnetic and dense for its size. Maybe a more seasoned rockhound or geologist may have some input!

Hello everyone. Hoping someone can help me with this artist signature. Thanks for any help.

Need a little bit of help, So came across this sort of oblong thick piece at a park in Southeast Pennsylvania. Was hesitant to pick it up wasn't sure if it was bone or something else can anyone identify it, especially most importantly if it's bone or not And if it is bone has it been modified...