✅ SOLVED What is this?

[ArDirtSlinger]

Ok I know this looks like a chunk of concrete... But I dug this at 8" and my pinpointer goes nuts over it.. the blueish color on the first pic really is what interests me.. Rusty type color on 2nd pic





When washing the dirt off under running water with tooth brush pieces would flake off..

Probably junk but thought I would ask anyway

 

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[Ant]

I would call it iron sulfide:
General Minerals - Images | Fundamental Photographs - The Art of Science