The surface of UV-stop quartz tube is clear or slight blue and its cut surface is light blue.Besides  its good physical and chemical capblities as common quartz tubes have, it also can filter out wavelength between 190-320nm,which stops the radiation to the body. It serves as the material of quartz halogen lamps ,high density discharge lamps and other UV light,which prevent the harm to the skin of people and things which have to be under the UV radiation .It sets out the maximum visible light at the same time .