Silver



Silver is a white, extremely lustrous metal, capable of taking a high polish. The use of silver in jewelry, tableware, and coinage is well known. The metal is usually alloyed with small amounts of other metals to make it harder and more durable.

Silver usually occurs in massive form as nuggets or grains, although it may also be found in wiry, treelike aggregates. When newly mined or recently polished, it has a characteristic bright, silver white color 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 jewelry in its pure or native 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, contains 20 to 25 percent silver. Sterling silver contains 92.5 percent silver or more pure silver, and Britannia silver contains 95 or more percent silver. Both alloys are used as standards to define silver content.

Most silver is a by-product of lead mining and is often associated with copper. The main silver mining areas of the world are South America, the United States, Australia, and Russia. The greatest single producer of silver is probably Mexico, where silver has been mined for nearly 500 years. The finest native silver, which occurs naturally in the shape of twisted wire, occurs in Kongsberg, Norway.