myjtp

I actually scored this piece for free a few days ago but I was wanting something thicker I can build a workbench around. But will this be good enough?

This is my first post but I have been lurking for a while. I read many times a nice thick piece of granite is the way to go for stamping leather. I had a guy message me off craigslist with this slab ( pic attached ). I assume this is a crazy good deal and i should jump on it and he will DELIVER it to my house! My question is ( probably stupid ) how can i tell if its real granite? Can you guys tell from this picture? Thanks!