Brass

Brass is a versatile manufacturing material because of its hardness and workability. Cameos were very popular in Ancient Rome and have enjoyed periodic revivals, notably in the early Renaissance, and again in the 17th and 18th centuries. A dezincified fitting has the pink appearance of pure copper and will easily crumble, being reduced to a weak sponge-like matrix. Cameos of great artistry were made in Greece dating back as far as the 6th century BC. In some territories, plumbing fittings designed to resist dezincification are embossed "CR" (corrosion resistant). Cameos are often worn as jewelry. In some environments, brasses with higher content of zinc are prone to a selective leaching corrosion known as dezincification. Sometimes dyes are used to enhance the colors.

The malleablity and acoustic properties of brass have made it the metal of choice for brass musical instruments such as the tuba. Alternately, a cameo can be made from (banded) agate, where different layers of the same stone have different colors. . This is then set upon the other type of material which provides a background of another color to offset the figure. Pure zinc, on the other hand, is too reactive to be produced by ancient metalworking techniques. One material is carved into a figure — the most common type being a profile portrait of a person's head. During this process, the zinc is extracted from the calamine and instantly mixes with the copper. A cameo is usually made of two types of material, commonly precious or semi-precious stone.

It was produced by melting copper together with calamine, a zinc ore. The terms "deep cameo" and "ultra cameo" describe cameo coins having the boldest, most attractive contrast. Brass has been known to man since prehistoric times, long before zinc itself was discovered. The effect of "cameo" also refers to a proof coin that has frosted lettering and features, providing attractive contrast with the mirrored fields of the coin. Because of this, and its relative resistance to tarnishing, it is often used as a decoration. It features a raised (positive) relief image; contrast with intaglio, which has a negative image. Brass has a yellow colour, somewhat similar to gold. Cameo is a method of carving, or an item of jewelry made in this manner.

. Despite this distinction, some types of brasses are called bronzes. Typically it is more than 50% copper and from 5 to 20% zinc^[1], in comparison to bronze which is principally an alloy of copper and tin.^[2]. Brass is the term used for alloys of copper and zinc in a solid solution.

Yellow brass is an American term for 33% zinc brass. White brass contains more than 50 % zinc and is too brittle for general use. Red brass is an American term for CuZnSn alloy known as gunmetal. Naval brass, similar to admiralty brass, is a 40% zinc brass and 1% tin.

Low brass is a copper-zinc alloy containing 20% zinc with a light golden color, excellent ductility and is used for flexible metal hoses and metal bellows. It has excellent machinability. Leaded brass is an alpha-beta brass with addition of lead. High brass, contains 65% copper and 35% zinc, has a high tensile strength and is used for springs, screws, rivets.

Common brass, or rivet brass, is a 37% zinc brass, cheap and standard for cold working. Cartridge brass is a 30% zinc brass with good cold working properties. Beta brasses, with 45-50 % zinc content, can only be worked hot, is harder, stronger, and suitable for casting. Arsenical brass contains an addition of arsenic and frequently aluminium and is used for boiler fireboxes.

Aluminium brass contains aluminium, which improves its corrosion resistance. Alpha-beta brasses are usually worked hot. It contains both α and β' phase; the β'-phase is body-centered cubic and is harder and stronger than α. Alpha-beta brass (Muntz metal), also called duplex brass, is 35-45 % zinc and is suited for hot working.

They contain only one phase, with face-centered cubic crystal structure. Alpha brasses (Prince's metal), with less than 35% zinc, are malleable, can be worked cold, and are used in pressing, forging, or similar. Admiralty brass contains 30% zinc and 1% tin which inhibits dezincification.