Silver

Silver (pronounced /ˈsɪlvɚ/) is a chemical element with the chemical symbol Ag (Latin: argentum, from the Ancient Greek: ἀργήντος - argēntos, gen. of ἀργήεις - argēeis, "white, shining" ) and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal. The metal naturally occurs in its pure, free form (native silver) and as an alloy with gold (electrum), as well as in various minerals, such as argentite and chlorargyrite. Most silver is produced as a by-product of copper, gold, lead, and zinc refining.

Silver has been known since ancient times and has long been valued as a precious metal, used to make ornaments, jewellery, high-value tableware and utensils (hence the term silverware) and currency coins. Today, silver metal is used in electrical contacts and conductors, in mirrors and in catalysis of chemical reactions. Its compounds are used in photographic film and dilute solutions of silver nitrate and other silver compounds are used as disinfectants. Although the antimicrobial uses of silver have largely been supplanted by the use of antibiotics, further research into its clinical potential is in progress.

Silver can be alloyed with mercury and tin at room temperature to make amalgams that are widely used for dental fillings. To make dental amalgam, a mixture of powdered silver and other metals is mixed with mercury to make a stiff paste that can be adapted to the shape of a cavity. The dental amalgam achieves initial hardness within minutes but sets hard in a few hours.Photography used 24% of the silver consumed in 2001 in the form of silver nitrate and silver halides, while 33% was used in jewelry, 40% for industrial uses, and only 3% for coins and medals. However its use in photography is dramatically declining because of the switch to digital technology.[citation needed]

Some electrical and electronic products use silver for its superior conductivity, even when tarnished. For example, printed circuits are made using silver paints, and computer keyboards use silver electrical contacts. Some high-end audio hardware (DACs, preamplifiers, etc.) are fully silver-wired, which is believed to cause the least loss of quality in the signal. Silver cadmium oxide is used in high voltage contacts because it can withstand arcing.

During World War II the short supply of copper brought about the government's use of silver from the Treasury vaults for conductors at Oak Ridge. (After the war ended the silver was returned to the vaults.) Source, Building Blocks of the Universe by Isaac Asimov.