silvering

Silvering is the chemical process of coating glass with a reflective substance. When glass mirrors first gained widespread usage in Europe during the 16th century, most were silvered with an amalgam of tin and mercury, but by the 19th century mirrors were commonly made through a process by which silver was coated onto a glass surface. Today, sputtering aluminium or other compounds are more often used for this purpose, although the process may either maintain the name "silvering" or be referred to as aluminising.