World currencies were once based on the Gold Standard and it is still, despite its weight, one of the most portable and desirable forms of money. Gold is highly ductile and may be beaten into microscopically thin sheets of gold leaf that have long been used to cover and ornament statuary and architecture. Gold does not oxidize or corrode, it retains its brightness. From time immemorial it has been used for making jewelry and ornaments as it is the shiniest metal. Silver has a bright coldness and in astrology it is associated with the moon.
Silver can gradually tarnish or oxidize to grey or black particularly in the presence of sulfides.
This property can be made use of to artificially oxidize silver to give it an old appearance. Base metals, and silver will oxidize slowly on the surface in the atmosphere. The resulting tarnish or patina colors the metal may or may not be desirable. Certain chemicals such as sulfides in the atmosphere or in perspiration can promote rapid tarnishing. It is easier to maintain a good finish, than to try and remove tarnish build up down the road.