Mosaic art is an ancient form of art that involves creating images with small pieces of colored glass, stone, or other materials. The material used by a mosaic artist to create their artwork is known as GROUT, which is a type of cement-like material that is used to fill in the gaps between the pieces of material used in the artwork. GROUT is typically made from a combination of sand, cement, and water, and it is used to hold the pieces of material together and give the artwork a finished look.