Why do silver or stainless steel earrings turn black?

Answer 1

The black coating on silver is silver oxide, silver tarnish, the silver equivalent of rust. The moisture and salt in perspiration accelerates oxidation, although even clean silver eventually oxidizes if left alone and exposed to air. Most silver needs to be polished once in a while.

Silver polished with silver polish on a soft cloth looks better than silver dipped in a chemical bath that dissolves the tarnish (or oxidation), because the chemical bath completely removes all traces of tarnish, even in the depressions, yet does nothing to make the highlights shiny. Polishing silver with a cloth leaves bright and shiny highlights that contrast with the dark oxide in the shadows.

Wax, like car wax, can help keep a silver bowl from turning black, but there is nothing (except plating, like gold plating) that will protect silver jewelry that is in contact with the skin.

Pure silver jewelry oxidizes the most quickly. There are silver alloys, like nickel-silver, that look like silver but resist oxidation. Be careful--the tarnish from a pure silver ring can turn your finger black.

Some misguided health buffs have ingested large quantities of "colloidal silver"-- a substance which allegedly kills internal bacteria but has the unfortunate side effect of turning your skin dark blue or even blue-black. If you do a Google picture search of "colloidal silver skin" you'll be amazed!

Answer 2

Silver earrings can turn black due to a chemical reaction with sulfur compounds in the air or on the skin, forming silver sulfide. Stainless steel earrings may turn black if the metal is not high quality and contains additional alloys that can react with oxygen or moisture, causing tarnishing. Regular cleaning and storing in a dry environment can help prevent this discoloration.