What Is Galena?


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John  Steele Profile
John Steele answered
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 exposed to acid mine drainage can be oxidized to anglesite by naturally occurring bacteria and archaea, in a process similar to bioleaching  Galena deposits are found in Wales, Germany, France, Romania, Austria, Belgium, 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 of 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, which 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, though silicon point-contact microwave detectors still exist in the market.
Muddassar Memon Profile
Muddassar Memon answered
Galena basically is natural mineral in the shape of lead sulphide. It is said to be the most vital lead ore mineral. Galena is also one the most highly found and distributed sulphide minerals.

It usually crystallizes in the cubic crystal system frequently displaying octahedral forms. It has generally been linked with minerals like sphalerite, calcite and fluorite. Galena deposits usually comprise of high quantities of silver in the form of silver sulphide mineral phases or as partial solid solution inside the galena structure.

For long periods these argentiferous galenas has been a vital ore of silver in mining. Selenium substitutes for sulphur in the structure constituting a firm solution series. Galena Deposits are located in number of places like France, Romania, Austria, Belgium, Italy, Spain, Scotland, England, Australia and Mexico.

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