Sterling silver, 925 silver, what does it mean?
Sterling Silver & Silver 925
Sterling silver and 925 silver are synonyms. Sterling silver is an alloy that contains 92.5 parts silver and 7.5 parts other metals, usually zinc and copper. To identify sterling silver jewelry, look for the abbreviation "925".
The origin of the word "Sterling" is believed to come from the term esterlin in the Middle Ages, a measure of weight used by silversmiths, which became a monetary unit. The English phonetics changed from esterlin to sterling.
Silver & Oxidation
Silver, like many other metals, oxidizes. With time, a dark layer is created by reaction with compounds in the air. This is a natural reaction that has nothing to do with the quality of the metal or jewelry. Certain types of skin (sweating) cause silver to oxidize faster and stronger, which can leave black marks on the skin.
Silver does not rust because it does not contain iron. Only metal-containing iron can rust.
Silver & Allergies
Silver is not known to create allergies, but people with very sensitive skin can react. For more information, read the article on Metals, Allergies and Oxidation.