>> Tuesday, April 28, 2009
Silver is found in mines primarily in Canada, Mexico, Peru, Bolivia, Australia and the United States.
Silver has been known since ancient times. It is mentioned in the Book of Genesis, and slag heaps found in Asia Minor and on the islands of the Aegean Sea indicate that silver was being separated 413from lead as early as the 4th millennium BCE. Silver was known to ancient civilizations, and evidence indicates that man learned to separate silver from lead in 3000 B.C.
Today sterling silver contains 92.5% silver, the remainder being copper or some other metal, and is used for silver jewelry and silverware where appearance is important. About 30% of silver produced is used in the photographic industry, mostly as silver nitrate. Silver is used in dental alloys, solder and brazing alloys, electrical contacts and batteries. Silver paints are used for making printed circuits. The metal is used to make mirrors, as it is the best reflector of visible light known, although it does tarnish with time.
Recorded use of silver to prevent infection dates to ancient Greece and Rome. It was rediscovered in the Middle Ages, where it was used for several purposes, such as to disinfect water and food during storage, and also for the treatment of burns and wounds as wound dressing. In the 19th century, sailors on long ocean voyages would put silver coins in barrels of water and wine to keep the liquid pure. Pioneers in America used the same idea as they made their journey from coast to coast. Silver solutions were approved in the 1920s by the US Food and Drug Administration for use as antibacterial agents. Today, wound dressings containing silver are well established for clinical wound care and have recently been introduced in consumer products such as sticking plasters.