AskDefine | Define galena

Dictionary Definition

galena n : soft blue-gray mineral; lead sulfide; a major source of lead

User Contributed Dictionary

English

Noun

  1. A mineral, lead sulphide (PbS), used as an ore for lead.

Translations

mineral
  • Croatian: galenit
  • Estonian: galeniit
  • Finnish: lyijyhohde

Extensive Definition

Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.
Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite.

Lead ore deposits

Galena deposits often contain significant amounts of silver as included silver sulfide mineral phases or as limited solid solution within the galena structure. These argentiferous galenas have long been the most important ore of silver in mining. In addition zinc, cadmium, antimony, arsenic and bismuth also occur in variable amounts in lead ores. Selenium substitutes for sulfur in the structure constituting a solid solution series. The lead telluride mineral altaite has the same crystal structure as galena. Within the weathering or oxidation zone galena alters to anglesite (lead sulfate) or cerussite (lead carbonate).
Galena deposits are found in Wales, France, Romania, Austria, Belgium, Italy, Gorno northern Italy, Spain, Scotland, England, Australia, and Mexico. Noted deposits include those at Freiberg, Saxony; Cornwall, Derbyshire, and Cumberland, England; the Sullivan Mine of British Columbia; and Broken Hill, Australia. Galena also occurs at Mount Hermon in Northern Israel. In the United States it occurs most notably in the Mississippi Valley type deposits of the Lead Belt in southeastern Missouri, and in similar environments in Illinois, Iowa and Wisconsin. Galena also was a major mineral of the zinc-lead mines of the tri-state district around Joplin in southwestern Missouri and the adjoining areas of Kansas and Oklahoma. Galena is also an important ore mineral in the silver mining regions of Colorado, Idaho, Utah and Montana. Of the latter, the Coeur d'Alene district of northern Idaho was most prominent.
Galena is the official state mineral of the U. S. states: Missouri and Wisconsin.

Galena uses

One of the earliest uses of galena was as kohl, which in Ancient Egypt, was applied around the eyes to reduce the glare of the desert sun and to repel flies, which were a potential source of disease.
Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. For example, it was used as the crystal in crystal radio sets, in which it was used as a point-contact diode to detect the radio signals. The galena crystal was used with a safety pin or similar sharp wire, and was known as a "cat's whisker". Making such wireless sets was a popular home hobby in the North of England during the 1930s. Derbyshire was one of the main areas where Galena was mined. Scientists that were linked to this application are Karl Ferdinand Braun and Sir Jagdish Bose. In modern wireless communication systems, galena detectors have been replaced by more reliable semiconductor devices, however, silicon point-contact microwave detectors still exist in the market.

References

Notes

galena in Bosnian: Galenit
galena in Catalan: Galena
galena in Czech: Galenit
galena in German: Galenit
galena in Estonian: Galeniit
galena in Spanish: Galena
galena in Esperanto: Galeno
galena in French: Galène
galena in Galician: Galena
galena in Italian: Galena
galena in Hebrew: גלנה
galena in Lithuanian: Galenitas
galena in Hungarian: Galenit
galena in Dutch: Galeniet
galena in Japanese: 方鉛鉱
galena in Norwegian: Blyglans
galena in Low German: Galenit
galena in Polish: Galena
galena in Portuguese: Galena
galena in Romanian: Galenă
galena in Russian: Галенит
galena in Simple English: Galena
galena in Slovak: Galenit
galena in Slovenian: Galenit
galena in Serbian: Галенит
galena in Finnish: Lyijyhohde
galena in Swedish: Blyglans
galena in Ukrainian: Галеніт
galena in Chinese: 方铅矿
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