Cupronickel in the context of "Full metal jacket (ammunition)"

Copper is a chemical element; it has symbol Cu (from Latin cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement.

Copper is one of the few native metals, meaning metals that occur naturally in a directly usable, unalloyed metallic form. This led to very early human use in several regions, from c. 8000 BC. Thousands of years later, it was the first metal to be smelted from sulfide ores, c. 5000 BC; the first metal to be cast into a shape in a mold, c. 4000 BC; and the first metal to be purposely alloyed with another metal, tin, to create bronze, c. 3500 BC.

Group 11, by modern IUPAC numbering, is a group of chemical elements in the periodic table, consisting of copper (Cu), silver (Ag), gold (Au), and roentgenium (Rg), although no chemical experiments have yet been carried out to confirm that roentgenium behaves like the heavier homologue to gold. Group 11, more specifically, the first three members are also known as the coinage metals, due to their usage in minting coins—while the rise in metal prices mean that silver and gold are no longer used for circulating currency, remaining in use for bullion, copper remains a common metal in coins to date, either in the form of copper clad coinage or as part of the cupronickel alloy. They were most likely the first three elements discovered. Copper, silver, and gold all occur naturally in elemental form.

Monel is a group of alloys of nickel (from 52 to 68%) and copper, with small amounts of iron, manganese, carbon, and silicon. Monel is not a cupronickel alloy because it has less than 60% copper.

Stronger than pure nickel, Monel alloys are resistant to corrosion by many aggressive agents, including rapidly flowing seawater. They can be fabricated readily by hot- and cold-working, machining, and welding.

Nickel silver, maillechort, German silver, argentan, new silver, nickel brass, albata, or alpacca is a cupronickel (copper with nickel) alloy with the addition of zinc. The usual formulation is 60% copper, 20% nickel and 20% zinc. Nickel silver does not contain silver, but resembles it, which can make it attractive as a cheaper and more durable substitute. It is also well suited for plating with silver.

A naturally occurring ore composition in China was smelted into the alloy known as paktong or báitóng (白銅) ('white copper' or cupronickel). The name German Silver refers to the artificial recreation of the natural ore composition by German metallurgists. All modern, commercially important, nickel silvers (such as those standardized under ASTM B122) contain zinc and are sometimes considered a variety of brass.

Toning on a coin is the change of colour brought about through oxidization, which forms a thin layer of tarnish on the metal's surface, typically as a result of interactions and chemical reactions with sulfur-containing compounds in the environment. Coin toning can vary in aesthetics, and thus can alternately add or detract from a coin's value. Coins with unusual toning colours or patterns tend to be valued by coin collectors. Toning is most common on silver coins, but can be found on coins minted from other metals and alloys, including gold, copper and cupronickel.

The 1 euro coin (€1) is a euro coin with a value of one euro. It is made of two alloys: the inner part of cupronickel, the outer part of nickel brass. All coins have a common reverse side and country-specific national sides. The coin has been used since 2002, with the present common side design dating from 2007.

As of July 2019, there were approximately 7.5 billion one-euro coins in circulation, constituting 25.3% of all circulated euro coins by value and 5.6% by quantity.

The British shilling, abbreviated "1s" or "1/-", was a unit of currency and a denomination of sterling coinage worth 1⁄20 of one pound, or twelve pre-decimal pence. It was first minted in 1503 or 1504 during the reign of Henry VII as the testoon, and became known as the shilling, from the Old English scilling, sometime in the mid-16th century. It circulated until 1990. It was commonly known as a bob, as in "ten-bob note", also the Scout Association's Bob a Job Week.

The shilling was last minted in 1966, prior to the UK's decimalisation. Following Decimal Day on 15 February 1971 the coin had a value of five new pence, and a new coin of the same value but labelled as "five new pence" (the word "new" was removed after 1980) was minted with the same size as the shilling until 1990. The five-pence coin was reduced in size in 1990, and the old larger five-pence coins and the pre-decimal shilling coins were both withdrawn from circulation at the end of the year. It was made from silver from its introduction in or around 1503 until 1946, and thereafter in cupronickel.