Calamine

:This article is about calamine in mineralogy. For other uses of the word, see the links at the bottom.

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Calamine is the common name for an ore of zinc.

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During the late 18th century it was discovered that what had been thought to be one ore was actually two distinct minerals:

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• zinc carbonate ZnCO₃ and
• zinc silicate Zn₄Si₂O₇(OH)₂.H₂O.

The two minerals are usually very similar in appearance and can only be distinguished through chemical analysis. The first to separate the minerals was the British chemist and mineralogist James Smithson in 1803. In the mining industry the term calamine is still used to refer to both minerals indiscriminately.

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In mineralogy there have been attempts to restrict the name calamine to one of these minerals, with the other called smithsonite after Smithson. Unfortunately there have been some differences over how to do this. To an American mineralogist, calamine is zinc silicate and smithsonite is zinc carbonate. To a British mineralogist, however, it is zinc carbonate that is usually called calamine. Zinc silicate is also known as hemimorphite.

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The International Mineralogical Association offer some guidelines as to the naming of minerals. They have defined calamine as the silicate of zinc. However, in practice, calamine may refer to either the silicate, the carbonate or both.

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Until the 18th century, "calamine" was the only source of zinc available to the brass manufacture industry, which as a result produced calamine brass.

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Hemimorphite and zinc spar are alternative names for the silicate and carbonate respectively.

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Ore: An ore is a mineral deposit containing a metal or other valuable resource in economically viable concentrations. Usually, it is used in the context of a mineral deposit from which it is economical to extract its metallic component. Ores are mined....

Zinc: Zinc (from German Zink) is a chemical element in the periodic table that has the symbol Zn and atomic number 30....

Minerals: REDIRECT Mineral...