Marble is a type of stone. Marble bath products are made of an imitation stone. Often called faux or cultured marble. It is not practical to carve tubs out of real stone. Just as a cultured pearl is a man induced pearl, a cultured marble tub is man made. Fine crushed stone is mixed with a polymer to create the matrix the tubs are fabricated from. Because of the polymer used, marble is actually fiberglass based in construction. But the wall structure is a thicker and does not have the laminated layers that acrylic and gel coat fiberglass units have. Cultured marble is usually colored to give the marbleized stone appearance and has a thin glossy resin top coat. Marble products can also be made with a solid color appearance which is usually referred to as onyx. Soaker tubs, jetted tubs, sink vanities, shower bases and shower wall panels are made from this polymer stone blend.