What is it and where is it formed?  Shale is a soft sedimentary rock.  It starts out as clay and then erosion moves it from place to place.  It falls into streams and forms a layer.  Lots of layers are added on top of the first layer.  The bottom layer is like a football player who has been tackled by ten players and is on the bottom of the pile.  He is being pressed down and lots of pressure is on him.  The bottom layer of clay is being pressed down by the weight of the layers on top.  The clay hardens and forms layers of shale.  Some shale becomes limestone and some changes into coal depending on what minerals are in them. Shale that is formed with heat and pressure becomes slate, a metamorphic rock. 

How and where is it mined?  Shale is mined using quarrying and open pit mining.  It is mined in the western United States.

What is it used for?  Shale is used in cement and bricks, concrete, and road construction, and ceramic products.