Today was my first day metal detecting and found this metallic rock. I was wondering what rocks set it off. Just trying to see if I can narrow down the list to identify this find. I’m in the middle TN region.
Yes, electricly conductive rocks can trigger a detector. They are called "hot rocks".
They are -thank good- rare in my little part of the world, its mostly alluvial soil here. I do have some lying around somewhere, though (mostly green = nice grade copper ore).
Around older homes you ll have to fight also coke/coal which kick the detector off (though these tend to have a unique signature, allowing to walk over them).
The stuff in question looks like slowtakon said, rather more than something melted (iron, alu) or slag than a natural rock.