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There is more information available on this subject at Brass on the English Wikipedia.

Brass is any alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties. In comparison, bronze is principally an alloy of copper and tin. Despite this distinction, some types of brasses are called bronzes. Brass is a substitutional alloy. It is used for decoration for its bright gold-like appearance; for applications where low friction is required such as locks, gears, bearings, ammunition, and valves; for plumbing and electrical applications; and extensively in musical instruments such as horns and bells for its acoustic properties. Brass has a muted yellow color, somewhat similar to gold. It is relatively resistant to tarnishing, and is often used as decoration and for coins. In antiquity, polished brass was often used as a mirror. Brass has likely been known to humans since prehistoric times, even before zinc itself was discovered. It was produced by melting copper together with calamine, a zinc ore.

Brass was still being used as a shell casing for firearms in 2552. Ash put spent brass casing on the graves of William and Dante.[1] It was also used for lamps. One of these lamps was found on Vice Admiral Ysionris Jeromi's Koa wood desk in 2551.[2]

In Halo, as well as present day military, senior commissioned officers are often referred to as "the Brass". The nickname was probably bestowed because their insignias are/were once made of brass.


  1. ^ Ghosts of Onyx, page 379
  2. ^ Ghosts of Onyx, page 104