I am a history major and this is my first time in AskHistorians so I will do my best to answer your question! (Mods be gentle)
Silver and gold have always been highly valued but their usage has helped to determine their values. Gold has often been associated with wealth due to its coinage. While other metals may be struck to form coins, the properties of gold allow for the metal to avoid being tarnished and thus retain its shiny luster and remain in circulation longer. As an example of the wealth silver has symbolized, highly polished silver was used to form the backings of early mirrors which were extremely difficult to produce and required skilled craftsmanship. For this reason the "hall of mirrors" in the Palace of Versailles was a testament to the immense wealth of Louis XIV. Both metals can be used to create wonderful works of art but since the price of art can be wildly subjective I would not use this as an accurate factor in the value of the metal.
The late 16th and 17th century saw an influx in silver and gold being shipped to Europe from the Americas under Spanish control. This increase in Spanish bullion caused economic hardships in Europe as markets attempted to adjust to the staggering amount of precious metals being brought back to the old world. From 1503 to 1650 16 million kilograms of silver and 185,000 kilograms of gold were shipped back through the Spanish port of Seville. The 16th century has often been called Spain's "Golden Age" but as you may notice, significantly more silver was being imported.
As more silver was imported prices in Spain rose. Along with a growth of population, Spain soon was consumed by rapid inflation notably in the price of silver. Silver was used by Spain to pay its armies and debts. For this reason silver can be credited for expanding Spain's influence during this time. The exchange rate from gold to silver during the 16th century was 1:10.7 this value for silver is significantly more than the 1:33.33 ratio of the 20th century but gold still remained "more valuable."
My Source for the history of the Spanish Golden age is my AP Euro textbook: "A History of Western Society" Sixth Edition John P. McKay, University of Illinois, Urbana-Champaign Bennett D. Hill, Georgetown University John Buckler, University of Illinois, Urbana-Champaign
You are a little mistaken. In the often repeated story it was Napoleon the third and the silver utensils he was reputed to use was aluminum not silver. Until the advent of the electrolytic process to refine aluminum it was very valuable. Sadly for the people with the aluminum objects after the process was invented in 1886 and it could be easily refined aluminum became incredibly cheap