Shale is a sedimentary rock while slate is a metamorphic rock formed from shale. Slate is much more durable than shale due to the metamorphic process it undergoes.
Slate and shale are similar in appearance. Visually, it can be hard to tell the two apart. Both types of rock break apart in layers and both types of rock also come in the same set of colors, with shades ranging from gray to black. The biggest difference, noticeable when handling the rocks, is in both the hardness and the different uses for each of the two unique types of rock.
Shale is the softer of the two rocks. It has a clay-like texture. In some cases, it is actually crushed and mixed with water to make types of clay, such as terracotta. Shale is also used in construction, where it is combined with limestone and then heated in order to make concrete and blocks. Finally, shale is a rich source of natural gas and oil.
Because it is so hard, slate is used as an end material in construction. Unlike shale's construction uses, which require extra steps, slate does not have to be broken down and mixed with other components. It is used for flooring, roofing and also to make pool tables and chalkboards.