Slate is a shallow metamorphic rock with a lamellar structure that can be formed by shallow metamorphism of various rocks, such as the clay rock, siltstone, siliceous rock, intermediate acidic tuff, carbonaceous rock and calcareous rock. The degree of metamorphism is very low, and the minerals are generally not recrystallized. The rocks are mainly clay slate, silty slate, siliceous slate, tuff slate, carbonaceous slate, and calcareous slate. Slate can be named by putting the name of the new metamorphic minerals in front, such as sericite clay slate and chlorite clay slate. Slate has a dense texture and fine grains with smooth cleavage surfaces.