**2. Clay mineral**

Clay is usually fine-grained materials, with particle size lower than 0.002 mm with majorly clay minerals. Other minerals related to clay minerals in clays might embody quartz and feldspar, along with detritic materials that have been eroded off the earth's surface. Clay minerals do not seem to be the most precious among the minerals on the face of the earth, but they affect life on the earth to a great extent. Clay is one of the most ancient mineral substances used by mankind. Clay is a widely dispersed, plentiful mineral resource with substantial industrial significance for a wide range of applications. It is one of the most important minerals in the world, both in terms of value and annual production. The term "clay," like many geological concepts, is vague and has numerous meanings: clay minerals are a group of fine-grained minerals with a particle size (smaller than silt) and a kind of rock—a fine-grained sedimentary deposit dominated by clay particles. Clay also includes fine-grained non-aluminosilicate deposits like shale and some argillaceous soils under the later definition. It was immensely essential in ancient civilizations, with records kept in brick structures, monuments, and pottery, as well as writings on clay tablets. Clay continues to be a fundamental raw material in today's world. Clay and clay compounds are now used in far too many ways to mention them all. Clay has a variety of industrial applications, including the manufacture of refractories and drilling mud in the water, oil, and gas sectors. The success of these research hinges on the appropriate exploitation of local raw resources for use as drilling mud in order to achieve long-term economic growth and job creation. Regardless of how abundant clay is and how widely it is used in industry, certain property standards must be satisfied by either raw or refined clay. Clay refining improves the geotechnical qualities of natural clays, potentially increasing their industrial potential. The raw materials used to make mud are generally chosen clays with a significant quantity of montmorillonite, and their behavior in water is utilized to appraise them. Their suitability is decided through numerous criteria, among which can be the viscosity, the volumetric yield of given clay and filtration characteristics. The bentonite clay is the raw material that satisfies the majority of these drilling criteria. Drilling for oil, gas, and water resources often necessitates a large volume of drilling mud, which is frequently imported into the nation. Apart from eroding the country's hard currency reserves, such importation is also incompatible with the country's present local content strategy for the oil industry. As a result, the necessity for bentonitic clays or comparable alternatives to be sourced locally has become critical.
