I have happened upon a few places where people have said that any rock that shows iron or rust is dangerous to have in your tank. But I have also found information from reputable sources which says it's fine. There are also various posts on threads where people have reported the safe use of rocks that were obviously rusting. This one is of course not obviously rusting...but still. It just adds to the confusion.
Naturally I'm confused...and I'm also not even sure if this is an iron vein or rust or what not. So I'm posting pictures. I'm assuming the rock is slate or possibly a very dense shale. The sediment layers are visible, it's dark gray, and it has passed the acid test. The magnet test came out negative as well. There's a whole deposit of this stuff in the woods near the PA turnpike a few miles away. I assume it was leftover surplus from the materials being used as a lower road layer.
Naturally I'm confused...and I'm also not even sure if this is an iron vein or rust or what not. So I'm posting pictures. I'm assuming the rock is slate or possibly a very dense shale. The sediment layers are visible, it's dark gray, and it has passed the acid test. The magnet test came out negative as well. There's a whole deposit of this stuff in the woods near the PA turnpike a few miles away. I assume it was leftover surplus from the materials being used as a lower road layer.
