This is a compact and impermeable sediment that turns into malleable plastic and is more or less thixotropic in water. Depending on its degree of refinement, it can have haracteristics showing physical or chemical variables. With its composition based on aluminosilicates, clay is present in raw materials used for manufacturing cement and hydraulic lime (30 to 40%). It is present in more or less great quantities in marls. Clay is generally full of impurities (mica, quartz,granite).
- See: "Marl."