Clay comes from the weathering and erosion of rocks, especially those containing the mineral group feldspar, over long periods of time. It typically forms in places where water once flowed or was present, such as old riverbeds, floodplains, ponds, lakes, and marine environments. The weathering process breaks down minerals and organic materials into fine particles that settle and accumulate as clay deposits. There are two main types of clay deposits: primary clays, which form and remain at the site of their origin, and secondary clays, which have been transported by water and redeposited elsewhere. Clay minerals form where rocks interact with water, air, or steam, through processes like chemical weathering and hydrolysis of feldspar-rich rocks, producing different types of clay minerals such as kaolinite and smectite.
