Silver is a chemical element (ag from latin argentum, derived from the greek ὰργὀς: shiny or white) and atomic number 47. Pure silver (1000) is soft, to make the metal workable it's mixed with copper resulting in a variety of alloys, all new precious matters jewelry are made with sterling silver: 925 parts silver / 75 parts copper (92,5% silver). Vintage jewelry is sometimes made of a second category alloy: 835 parts silver / 165 parts copper (83,5% silver).
To keep your silver items beautiful make sure to sleep, shower, swim, perform household chores, sport without them.
oxidized silver }
Silver will eventually change from white to black due to oxidation. Totally black silver items are oxidized through a chemical process, the blackness is always a very thin layer, it will wear of a bit in time.
2,5 - 3 on the scale of mohs. Glossy becomes a bit matte, matte becomes a bit glossy over time.