Mineral resource of the month: silver

Silver, one of the eight precious or noble metals, has been used extensively throughout recorded history for various medical purposes, ornaments and utensils, and for its intrinsic value as the basis for trade and monetary systems. Silver has played a significant role in world history, financing a Greek victory over the Persians in 480 B.C., helping Spain become a world power in the 16th and 17th centuries, and helping fund the Union forces during the U.S. Civil War, to give a few examples.

Silver occurs as a native metal; in sulfide ores of copper, lead and zinc; and sometimes with bismuth and antimony. Silver is always present in ores containing gold. The Silver Institute estimated that, in 2013, about 29 percent of global mined silver came from silver ores, 38 percent came from lead-zinc ores, 20 percent came from copper ores and 13 percent came from gold ores.

Silver's properties include its ability to endure extreme temperatures, its high reflectance of light, its thermal and electrical conductivity (the highest of all metals), and its strength, malleability and ductility. Demand for silver arises from three areas: industrial applications (in electronics, brazing alloys and solders, photography and other uses), investment (including coins and bars), and silver jewelry and decor (including silverware).

Silver-halide X-rays were long the standard, but are now being replaced by digital imaging technology. Since 2000, demand for silver in photographic applications has also declined owing to the use of digital photography. In 2013, uses in electronics accounted for 42 percent of U.S. silver consumption; coins and metals for 35 percent; photography for 13 percent; jewelry and silverware for 7 percent; and other uses for 3 percent.

Silver is also used in solar power generation: 90 percent of crystalline silicon photovoltaic solar cells use silver paste. On windows, a transparent layer of silver reflects up to 95 percent of sunlight, saving energy. In water purification, use of silver eliminates the need for corrosive chlorine.

For more information on silver and other mineral resources, visit: http://minerals.usgs.gov/minerals.