The two most common materials used to construct a pool table are FELT and SLATE. FELT is a type of fabric made from wool, cotton, or synthetic fibers, and is usually dyed in a variety of colors. SLATE is a metamorphic rock composed of clay minerals and quartz, and is often used as a building material due to its durability and strength. Both materials are essential for constructing a pool table, as the FELT provides a smooth surface for the balls to roll on, while the SLATE provides a flat and level playing surface.