Sandstone is composed of quartz grains (sand), which is stable in structure, usually light brown or red. Sandstone is a sedimentary rock, mainly formed by cementation of sand, the sand content should be greater than 50%. Most of the sandstone is composed of quartz or feldspar. The main component of A. quartz composition of more than 52%; B. clay around 15%; C. goethite about 18%; D. other substances more than 10%.
The tiny particles formed by the hardening of shale material are easily broken and broken, which can easily be split into distinct layers. A kind of clay. The composition is complex and contains many detrital minerals and authigenic minerals. Sheet or sheet bedding. Hit with a hard object. It is formed by compaction, dehydration and recrystallization. The ability of shale to resist weathering is weak, and it is often eroded to form low mountains and valleys. Shale is impervious to water, and often becomes an impermeable layer in the distribution of groundwater.
Shale, shale is a sedimentary rock, complex composition, but having a thin sheet or sheet laminated joints is mainly formed by clay deposited by the pressure and temperature of rock, but mixed with detrital quartz, feldspar and other chemicals.
