What is repousse?
A method of forming a pattern on metal by stamping, hammering or pressing a design from the back to produce a three-dimensional bas-relief surface on the front.
100% solid silver won't tarnish but it is too soft to use for making jewelry - it could easily be scratched, dented and bent. Sterling silver has a small amount of one or more other metals usually copper, added to the silver. To be called sterling silver, the alloy must contain at least 92.5% pure silver. Sterling silver alloy is harder than pure silver but the added metals also can cause discoloration or tarnish.