Abstract: A method of adhering a metal to a surface of a substrate of silica, quartz, glass or sapphire is set forth. The surface to be metallized is first roughened by mechanical abrasion to obtain a roughness lying between 0.2 .mu.m and 0.7 .mu.m and is then subjected to a chemical treatment of etching by immersion in an aqueous solution of HF. According to the invention, the method further comprises the following steps of ion etching of the surface down to a depth less than 30 nm and then applying to the surface a first metallic adherence layer by cathode sputtering.