Slate is formed when high pressures are exerted on a sedimentary rock like shale. It is a dark, fine-grained stone made up of thin, sedimentary layers that allow it to be split into thin slabs, often used for roof tiles.
in. how are the folks there coping and dealing? reporter: i think as best as you can expect. i think a lot of them have a very good demeanor and a nice perspective of what happened here. we re on the campus of shaw university in downtown raleigh. i want to show you one thing in particular. see the building behind me here? that s the gymnasium, up on the ro roof, a little bit of roof damage. these are the slate tiles and these are these are solid. they weigh 8 to 10 pounds a piece, have very sharp edges and these became projectiles when the tornado came through texas and those kind of litter the landscape here. the tornadoes came right through texas, national weather service storm surveyors say weak ef-0 tornado. usually trees this big, it takes a good 100-mile-an-hour wind or stronger to knock them over. this is a three-foot diameter