Borax, also called coarse borax, is a soft and light colorless crystalline substance. In chemical composition, it is a sodium tetraborate containing 10 water molecules. Its crystals are plate-shaped or columnar, and the crystals gather together to form a cluster-shaped, granular, porous clod, etc. The color is gray in white or yellow, blue and green with light tones, and it has a glass luster. Borax has many uses that we are familiar with, such as.