In the US, using this to back currency was promoted by the bimetallism movement.
The city of Shemnitz was known for its production of this resource in medieval times, while the Grecian city of Laurium was a major source of this resource in the ancient world. Its discovery in one nation led to boomtowns like Virginia City. European powers' replacement of this trade medium led to the Opium Wars. The Spanish used the mita system to provide labor for the mining of this resource at sites like Potosi. In the US, using this to back currency was promoted by the bimetallism movement. For 10 points, name this resource that was championed in William Jennings Bryan's Cross of Gold Speech and is frequently used in coins and jewelry.
The city of Shemnitz was known for its production of this resource in medieval times, while the Grecian city of Laurium was a major source of this resource in the ancient world.
silver [or Ag]