Absolutely not! The previous answer was quite misleading. Many countries, independent artists, etc etc use silver and never stamp it, as well as stamps can be worn down over the years. After enough...
In the U.S., "coin silver" is the term for the alloy of 90% silver and 10% copper that was used to mint dimes, quarters and halves up to 1964, and dollars up to 1935. Sometimes silverware makers...
Probably some of the absolute best Sterling Silver Jewelry is made in Italy. Total quality. It may cost more but you are sure to receive the best in quality and workmanship.