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 What
is silver?
Silver is a
ductile, malleable, brilliant greyish-white metal.
The
chemical symbol for silver is Ag, meaning 'argentum'
- an ancient or poetic word for silver. The term
'sterling' for English currency denotes a specific weight of
silver. When we say something is 'sterling' we mean
'excellent'.
The
price of silver and other precious metals is quoted in terms
of troy ounces. The term 'troy' is derived from Troyes,
France, a major trading city of the Middle Ages. One troy
ounce equals 31.1 grams.
What are the properties of silver?
Silver has the
highest electrical and thermal conductivity of any metal. It
is malleable (easily shaped), ductile (can be drawn into
very thin wire) and has antiseptic properties.
Occurrence
Silver ranks about 66th among elements in natural abundance
in crustal rocks. It occurs in the pure state to a
small extent; the most notable deposits of native silver are
in Peru and Norway, where the mines have been worked for
centuries. Pure silver is also found associated with
pure gold in the form of an alloy known as electrum,
and considerable amounts are recovered in the processing of
gold. Silver is usually found combined with other
elements (of which sulfur is the most predominant) in
minerals and ores. Some of the important silver
minerals are cerargyrite (or horn silver), pyrargyrite,
sylvanite, and argentite.
Silver also occurs as a constituent of lead, copper, and
zinc ores, and half the world production of silver is
obtained as a by-product in the processing of such ores.
Practically all the silver produced in Europe is obtained
from the lead sulfide ore,
galena. In the United States, relatively few mines
are worked for their silver alone—the silver is mined in
conjunction with lead, copper, and zinc. In 2003, U.S. mines
produced 1,240 metric tons of silver, about one-eighth of
the production worldwide. Most of the silver mined in
the world comes from Mexico, the United States, Peru,
Australia, and Canada. The leading silver-producing states
in the United States are Nevada, Idaho, Alaska, and Arizona.
(source: Encarta)
see also:
Silver Metallurgy
What has silver been used for in the past?
Silver has had
many practical and artistic uses. Because it was found as a
free metal and was easy to work it was put to a variety of
uses. The early discovery that water, wine, milk and vinegar
stayed pure longer in silver vessels, led to its use as a
container for long voyages on land and sea over 2,500 years
ago.
What is silver used for today?
The many
properties of silver mean that it is widely used today in
science and technology. Each year over 7,000 new patents and
papers are published which describe a product or process in
which silver is a vital part.
Silver
has a range of specialised electrical, mechanical, optical
and medicinal properties. Silver is used in solar panels and
spacecraft, plumbing and pendants. It has not been an easy
metal to replace as new technology reveals additional
applications.
Technology
The photographic
industry takes 35% of the silver used each year throughout
the world. Silver halides, coupled with dyes produce colour
photographic images. X-Ray and black & white photography
also rely on silver.
Watches,
cameras and calculators use silver in their batteries to
provide higher voltage and longer life. Silver oxide-zinc
batteries, which have twice the electrical capacity of
lead-acid batteries of the same size, are used extensively
in aircraft and submarines, where weight is critical.
Silver
concentrates the sun’s rays on solar collectors, It is found
on the backs of mirrors and protects the heat-reflecting
gold film on windows. Under the keys of almost every
personal computer is a panel of switches with silver
contacts to carry out the countless millions of
instructions.
Silver
thiosulphate prevents the release of ethylene gas from cut
flowers to produce longer lasting blooms destined for
export. Silver can be prepared as crystals of silver iodine
and seeded into cold cloud to produce raindrops or
snowflakes.
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