SILVER.
Silver
usually occurs in massive form as nuggets or grains, al
though it may also be found in wiry, dendritic (tree-like)
aggregates. When newly mined or recently polished, it has a
characteristic bright, silver-white colour and metallic luster.
However, on exposure to oxygen in the air a black layer of
silver oxide readily forms, tarnishing the surface. Because
of this, and the fact that it is too soft to be used in most
jewellery in its pure form, silver is often alloyed with
other metals, or given a covering layer of Gold. Electrum,
an alloy of gold and silver in use since the time of the
Ancient Greeks, contain 20-25 per cent silver. Sterling
silver contains 951/2 per cent or more pure
silver (and usually some copper), and Britannia silver has a
silver content of 95 per cent or more. Both alloys are used
as standards to define silver content.
Occurrence
Most silver is a by-product of lead
mining, and is often associated with copper. The main silver
mining area of the world are South America, the USA,
Australia, and the former USSR. The greatest single producer
of silver is probably Mexico, Where silver has been mined
from about AD1500 to the present day. The finest native
silver, which occurs naturally in the shape of twisted wire,
is from Kongsberg, Norway.
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TOWER
BROOCHES
These
modern silver brooches, made by British silvermith,
V.Ambery-smith, have additional decoration in red and
yellow gold
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POLISHED
SLICE
OF SILVER
AND COPPER
ORE
Polished Silver
Patches of
copper |
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SILVER
WINE CUP
This part-gilt
silver cup was fashioned in 1493, when silver
was valued as highly as gold |
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oxidation alters
colour of silver. |
SILVER
DISH
Fashioned in
1973, this dish features a leaf motif border
made from oxidized silver.
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