Silver
Silver is a metal element denoted by the atomic symbol, Ag (derived from the Latin name argentum). It has an atomic number of 47 and an atomic weight of 107.868. It is a white solid that is extraordinarily malleable and ductile. It has a melting point of 1763.2°F (961.78°C) and a boiling point of 3923.6°F (2162°C).
For thousands of years silver has been highly valued as a precious metal because of its relative scarcity. It is often associated with gold as a symbol of wealth or status. Though it has been less valuable than gold in most cultures, it is preferable for some purposes because it is harder and therefore more durable than gold. Silver occurs naturally and in ores, like argentite, horn silver, and hessite. About one-half of the world's silver is mined in North America, but Russia, Peru, and Australia are major producers as well. After the silver is mined, it is refined by heating the metal until the impurities rise to the surface. This process is called smelting.
Historically, silver has been among several metals used for making coins, medallions, and artifacts in Greece, Rome, Assyria, and other parts of the Mediterranean. Lozenge-shaped pieces of silver with no set value were used in trade in Lydia (Asia Minor) around 640 B.C. , however, the world's first standardized coinage was issued by the Lydian King Croesus (reigned 560-546 B.C. ). The innovation helped establish Croesus' reputation for wealth, and it was so successful that silver coins appeared in Persia, India, and China in relatively short time. Chinese silver coins, round with square holes in them, continued to be minted in the same basic size and shape from approximately 500 B.C. to the early twentieth century.
In addition to its use in currency, silver has also been used in jewelry, religious artifacts, ornaments, and tableware. Then it is sometimes combined with other metals such as lead or gold. It can be alloyed with copper to make sterling silver. The copper adds an element of strength so coins, silverware and jewelry can be used for a longer period of time. A silver nitrate compound can be applied as silver plating, which is used in mirrors and cheap tableware.
Silver is an unparalleled conductor of heat and electricity. It can be easily drawn into wire, but, copper and aluminum are preferred for this purpose because they are less expensive to use. Silver can also be worked into extremely thin leaf, thinner than a coat of paint. Leaf silver is used to coat less costly metals.
About 30% of the world's silver supply goes into coinage or as bullion reserve as legal backing for paper money. The United States retired its silver certificates in 1963 and replaced them with Federal Reserve notes. Many countries, including the United States, have reduced or eliminated the silver content of coins because the value of the metal often exceeds the face value of the money.
Another 30% of silver produced is used in the photographic industry. Silver nitrate is the compound most used for film and darkroom materials. Other applications of silver include the use of silver iodide capsules in cloud seeding and medicine. Silver is also a component of dental alloys. Additionally, it has been used to purify drinking water because it is generally toxic to bacteria and fungi. Jewelers use silver as a soft solder in making jewelry. Cadmium batteries are made with zinc and silver.
This is the complete article, containing 566 words
(approx. 2 pages at 300 words per page).
