Shale gas refers to natural gas that is found in shale formations. Shale is a fine-grained sedimentary rock composed mainly of clay minerals, and it can contain hydrocarbons such as natural gas. The extraction of shale gas involves the process called hydraulic fracturing or fracking, where water, sand, and chemicals are injected into the well at high pressure to crack open the rock and release the trapped gas. Shale gas has become an important source of energy in many countries due to its abundance and relatively low cost of production compared to other sources such as coal or oil.