So, I found this stone mantel behind the garage of the 100 year old house we just bought. It was mostly buried in the dirt. Fits our mantel perfect. Some sort of green stone. Was painted black at some point. I'm trying to strip the paint and want to refinish the stone. Area is southeast of Pittsburgh. Father of the man who built the house was an Italian stonemason that immigrated.
Don't think it's slate, has a tight grain and rings when you knock on it.
What kind of stone is this?
That's slate. Very sure. It's a common building material (especially roofing) where it can look and act like that.
Shale is similar. I have a lot of shale deposits nearby, and I can say that stripping paint with a paintbrush would likely break little bits off of it. It's way to fragile to do anything with it. It would be exceedingly difficult to cut it to that shape and keep it that way, as well.
Looking into it more, I agree that it's slate. Didn't realize it could be this size, only ever heard of it being used for tiles.
Expensive pool tables are often a solid sheet of slate, since its quite smooth and flat.
Learned that when I was recruited to help put the top in place on one.