Silver is a metallic chemical element with the chemical symbol Ag (Latin: argentum) 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.
Silver has long been valued as a precious metal, and it is used to make ornaments, jewelry, high-value tableware, utensils, and currency coins. Today, silver metal is also used in electrical contacts and conductors, in mirrors and in catalysis of chemical reactions.
While it was believed werewolves were vulnerable to silver, in reality this was not the case. For instance, in 1176, a werewolf named Dieter sought sanctuary in Saint Cäcilien's in wolf form. He frightened a priest who struck him with his staff that had a silver crucifix on the end. The blow hurt Dieter as much as it would have if he were a human, but the silver did not cause him any specific harm.
Silver was among the metals the Krolp prized. Fifty years after their first arrival, the Krolp discovered a deposit of silver (and a small amount of gold) deep below the surface of northeastern Utah within the territory of the rump United States and Canada. Despite a treaty recognizing the sovereignty of the U.S., the Krolp demanded access to the silver. U.S. President/Canadian Prime Minister Harris Moffatt III realized that the Krolp's mining efforts would probably leave what was left of his two countries uninhabitable, and staged a desperate, doomed uprising. In the end, the Krolp got their silver and gold.
Iron, another metal used as a repellent against supernatural threats in fantasy lore.
↑Amazing Stories, vol 57, no. 3, September 1983, pg. 122.