Brass is an alloy of copper and zinc, in proportions which can be varied to achieve varying mechanical and electrical properties.
It is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure. Brass is similar to bronze, another alloy containing copper, with tin in place of zinc; both bronze and brass may include small proportions of a range of other elements including arsenic, lead, phosphorus, aluminum, manganese, and silicon.
Brass has long been a popular material for decoration for its bright gold-like appearance, e.g. for drawer pulls and doorknobs. It has also been widely used for all sorts of utensils due to many properties, such as low melting point, workability (both with hand tools and with modern turning and milling machines), durability, electrical and thermal conductivity.
It is commonly used in applications where low friction and corrosion resistance is required, such as locks, hinges, gears, bearings, ammunition casings, zippers, plumbing, hose couplings, valves, and electrical plugs and sockets. It is also used extensively for musical instruments such as horns and bells. Brass is often used in situations in which it is important that sparks not be struck, such as in fittings and tools used near flammable or explosive materials.