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.

The earliest mirrors were made from polished obsidian during the Stone Age. By the Bronze Age most cultures had adopted mirrors made from polished discs of bronze, copper or other metals. Such metal mirrors remained the norm through to Greco-Roman Antiquity and throughout the Middle Ages in Europe. In the 1st century CE glass mirrors began to appear, now believed to have originated in Sidon in present-day Lebanon.Ptolemaic Egypt had manufactured small glass mirrors backed by lead, tin, or antimony. In the early 10th century, the Persian scientist al-Razi described ways of silvering and gilding in a book on alchemy, but this was not done for the purpose of making mirrors.

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