Scientists that were linked to this application are Karl Ferdinand Braun and Sir Jagdish Bose.
The galena crystal was used with a safety pin or similar sharp wire, and was known as a "cat's whisker". 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. Galena is a semiconductor with a small bandgap of about 0.4 eV which found use in early wireless communication systems. 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 the official state mineral of the U. Of the latter, the Coeur d'Alene district of northern Idaho was most prominent. Galena is also an important ore mineral in the silver mining regions of Colorado, Idaho, Utah and Montana. 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. 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 occurs at Mount Hermon in Northern Israel. Noted deposits include those at Freiberg, Saxony Cornwall, Derbyshire, and Cumberland, England the Sullivan mine of British Columbia and Broken Hill, Australia. Galena deposits are found in Wales, France, Romania, Austria, Belgium, Italy, Spain, Scotland, England, Australia, and Mexico. Within the weathering or oxidation zone galena alters to anglesite (lead sulfate) or cerussite (lead carbonate). The lead telluride mineral altaite has the same crystal structure as galena. Selenium substitutes for sulfur in the structure constituting a solid solution series. In addition zinc, cadmium, antimony, arsenic and bismuth also occur in variable amounts in lead ores. These argentiferous galenas have long been the most important ore of silver in mining. Galena deposits often contain significant amounts of silver as included silver sulfide mineral phases or as limited solid solution within the galena structure.
It is often associated with the minerals sphalerite, calcite and fluorite. It crystallizes in the cubic crystal system often showing octahedral forms. Galena is one of the most abundant and widely distributed sulfide minerals. It is the most important lead ore mineral.
Is the natural mineral form of lead sulfide.
GERMANIO E SILICIO FREE
Macro de Galena ou sulfeto de chumbo natural (Fórmula química: PbS) - 172Ī text, in english, from Wikipedia, the free encyclopedia:
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