The gather rate of rare resources can be increased in various ways, as described in the main article. Note that Metal is not gathered until a nation has entered the Classical Age and linking a Silver resource while still in the Ancient Age might not provide the full benefit.
Silver is one of the five rare resources to reduce research cost, with the other four being Dye, Furs, Papyrus and Silk. Due to the high cost of age advances, early linking of this resource can save a nation lots of resources, most notably Knowledge, which is required for all advances after the Classical Age. This holds especially true, when playing with one of the "long and expensive research" options.