Copper and its alloys, including brasses and bronzes, are ubiquitous in functional items and the decorative arts. Copper is usually red/pink in colour. Oxidation, a corrosion process, produces a dark red-brown patina. Copper saucepans, brass door fittings and bronze sculptures all have copper as their main constituent. Copper is also present in small quantities in silver, gold, Britannia metal and many other alloys.
In modern usage, brass refers to an alloy of predominantly copper and zinc, whilst bronze refers to an alloy of predominantly copper and tin. However, many historic copper alloy objects contain both zinc and tin, and so the term 'copper alloy' is often used if the exact composition is not known. Copper and its alloys were often patinated, which can also cause confusion.