The Spaniards during the 16th century AD found one of the most important silver mines. The largest active mines now include those at Hildago, Mexico. By at least the 8th century BC most likely all countries of the ancient Middle East were using both silver and gold as currency. A prohibition was placed on silver coinage in the US in 1873 as a result of the gold discoveries in the mid-19th century. In the 1960's the Treasury Department ceased issuing silver certificates, the paper money secured by silver.
Silver is a heavy metallic element with a brilliant white luster.
Although not as expensive as gold, it is still costly and rare. Silver ranks 65th in cosmic abundance and about 68th in abundance in the Earth's crust. Next to gold, it's the most malleable and ductile metal. It's harder than gold but softer than copper. It's also the best conductor of heat and electricity of any other metals.