Nickel

Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile. Pure nickel shows a significant chemical activity that can be observed when nickel is powdered to maximize the exposed surface area on which reactions can occur, but larger pieces of the metal are slow to react with air at ambient conditions due to the formation of a protective oxide surface. Even then, nickel is reactive enough with oxygen that native nickel is rarely found on Earth's surface, being mostly confined to the interiors of larger nickel–iron meteorites that were protected from oxidation during their time in space. On Earth, such native nickel is found in combination with iron, a reflection of those elements' origin as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's inner core.

The use of nickel (as a natural meteoric nickel–iron alloy) has been traced as far back as 3500 BCE. Nickel was first isolated and classified as a chemical element in 1751 by Axel Fredrik Cronstedt, who initially mistook its ore for a copper mineral. The element's name comes from a mischievous sprite of German miner mythology, Nickel (similar to Old Nick), that personified the fact that copper-nickel ores resisted refinement into copper. An economically important source of nickel is the iron ore limonite, which often contains 1-2% nickel. Nickel's other important ore minerals include garnierite, and pentlandite. Major production sites include the Sudbury region in Canada (which is thought to be of meteoric origin), New Caledonia in the Pacific, and Norilsk in Russia.

Nickel (surname)

Nickel is a surname. Notable people with the surname include:

Nickel (United States coin)

A nickel, in American usage, is a five-cent coin struck by the United States Mint. Composed of 75% copper and 25% nickel, the piece has been issued since 1866.

The silver half dime, equal to five cents, had been issued since the 1790s. The American Civil War caused economic hardship, driving gold and silver from circulation; in response, in place of low-value coins, the government at first issued paper currency. In 1865, Congress abolished the five-cent fractional currency note after Spencer M. Clark, head of the Currency Bureau (today the Bureau of Engraving and Printing), placed his own portrait on the denomination. After successful introduction of two-cent and three-cent pieces without precious metal, Congress also authorized a five-cent piece consisting of base metal; the Mint began striking this version in 1866.

The initial design of the Shield nickel was struck from 1866 until 1883, then was replaced by the Liberty Head nickel. The Buffalo nickel was introduced in 1913 as part of a drive to increase the beauty of American coinage; in 1938, the Jefferson nickel followed. In 2004 and 2005, special designs in honor of the bicentennial of the Lewis and Clark Expedition were issued. In 2006, the Mint reverted to using Jefferson nickel designer Felix Schlag's original reverse (or "tails" side), although a new obverse, by Jamie Franki, was substituted. As of the end of FY 2013, it cost more than nine cents to produce a nickel; the Mint is exploring the possibility of reducing cost by using less expensive metals.