In very rare cases silver is found in a native form as nuggets in placer deposits and veins. Much more common are polymetallic deposits with silver, commonly combined with sulfur, arsenic, antimony, or chlorine. Ores such as argentite (Ag2S), chlorargyrite (horn silver, AgCl), and galena, which is actually a lead ore, which often contains significant amounts of silver. It is often found in conjunction or alloyed with other metals and is extracted through amalgamation or electrolysis.
Silver is mined since the 5th century BCE. It is a precious metal often used for coins and bullion, as a result its mining has often been lucrative. Ancient Athens based its currency on the silver mines at Laurion or Laurium. The Romans mined silver in Spain in mines they took over from Carthage after the Second Punic War. In Roman Britain, soon after the Roman conquest, silver was extracted from lead ore. From the 15th century silver was extracted from copper ores in massive quantities using the liquation process. Centers of Medieval silver mining were in the Erzgebirge (Ore Mountains) in Germany and Schwaz in Austria. Discoveries of silver ore deposits have sparked silver rushes of miners seeking their fortunes. After the discovery of large deposits in the Americas, the European silver mining more or less collapsed, while silver mining in the Americas was devastating for the indigenous people which were forced to work in the mines. The most important silver mine in the Americas was Potosi, discovered in 1545.
Silver processing has led to significant environmental impacts. For patio amalgamation, mercury was a key component in the process. Since the patio process was first used 250,000 tonnes of mercury were lost to the environment in the Americas. Mercury poisoning has severe health effects and can be deadly, and the released mercury evaporates into the atmosphere and creates the global mercury cycle. And even in modern days people in poor countries use mercury in the search for silver and gold, poisoning themselves and the environment in the process.
Today the top producers of silver are located in Australia, Mexico, Bolivia, and Peru.