What causes silver jewelry to turn black over time?

Answer: Sulfur in the air reacts with silver atoms on the surface

Sulfur in the air reacts with silver atoms on the surface ✓ — Correct! Trace amounts of hydrogen sulfide gas (H₂S) float in the air—from eggs, rubber bands, car exhaust, and natural sources. When these sulfur compounds land on silver, they react with the silver atoms to form silver sulfide (Ag₂S), a black compound. This black layer builds up gradually. This explains why silver tarnishes faster near rubber, eggs, or in polluted cities. Gold doesn't tarnish because it's too chemically stable to react with sulfur. You can remove tarnish by polishing (grinding it off) or using aluminum foil with baking soda (which chemically reverses the reaction).

Oxygen rusts the silver the same way it rusts iron — Wrong. Silver doesn't rust like iron. Rust is specifically iron oxide formed when iron reacts with oxygen and water. Silver is far more resistant to oxygen than iron. Silver's black tarnish comes from sulfur compounds in the air, not oxygen.

Silver naturally darkens with age like an old photograph — Wrong. Silver doesn't change color due to age alone. It needs to react with something. Fresh silver kept in an airtight container stays shiny indefinitely. The blackening only happens when sulfur compounds in the air react with the silver surface.