Calamine (mineral)
Calamine is a historic name for an ore of zinc. The name calamine was derived from lapis calaminaris, a Latin corruption of Greek cadmia (καδμία), the old name for zinc ores in general. The name of the Belgian town of Kelmis, La Calamine in French, which was home to a zinc mine, comes from that. In the 18th and 19th centuries large ore mines could be found near the German village of Breinigerberg.
During the early 19th century it was discovered that what had been thought to be one ore was actually two distinct minerals:
- Zinc carbonate ZnCO3 or smithsonite and
- Zinc silicate Zn4Si2O7(OH)2·H2O or hemimorphite.
Although chemically and crystallographically quite distinct, the two minerals exhibit similar massive or botryoidal external form[1][2] and are not readily distinguished without detailed chemical or physical analysis. The first person to separate the minerals was the British chemist and mineralogist James Smithson in 1803.[3] In the mining industry the term calamine has been historically used to refer to both minerals indiscriminately.
In mineralogy calamine is no longer considered a valid term. It has been replaced by smithsonite and hemimorphite in order to distinguish it from the pinkish mixture of zinc oxide (ZnO) and iron(III) oxide (Fe2O3) used in calamine lotion.
Until the 18th century, calamine was essential for the production of brass since metallic zinc does not exist in nature and no technique was known to produce it. Brass produced using calamine is called calamine brass.
References
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Wikisource has the text of the 1911 Encyclopædia Britannica article Calamine. |
- ↑ Hemimorphite on Webmineral
- ↑ Smithsonite on Webmineral
- ↑ Goode, George Brown (1897). The Smithsonian Institution, 1846-1896, The History of Its First Half Century. Washington, D.C.: De Vinne Press. pp. 12–13.