In a known component having a reflector layer, the surface of a base body of quartz glass is covered at least in part with a reflector layer. Starting from this, to provide a component, particularly for use in lamp and reflector manufacture, which is equipped with an efficient, chemically and thermally resistant and, nevertheless, inexpensive reflector layer, it is suggested according to the invention that an SiO.sub.2 cover layer should be provided which acts as a diffuse reflector and consists of at least partly opaque quartz glass.