Everything about Galena totally explained
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.
Further Information
Get more info on 'Galena'.
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