Barium sulfate sand is an important radiation protection material. Its main component is natural barium sulfate (BaSO₄), which has a high density (4.3-4.5 g/cm³) and a high atomic number, effectively blocking X-rays and gamma rays. It is applied on-site by mixing with cement and pouring or plastering to form a seamless, continuous, high-density protective layer, offering both flexibility and economy.