925 refers to the 92.5 percent content of silver in the
alloy. The other 7.5 percent usually consists of copper, which does not change
the color of silver but adds to its hardness.
Silver turns black when it reacts with sulfur in
the air and in perspiration. Silver
containing copper, a more reactive metal, will tarnish and dull. Buy a silver
polish or silver cloth to clean it before heavy buildup.
The metal known as German silver is an alloy made of copper,
nickel, and zinc. It resembles silver in appearance, may be engraved, and is
much harder than sterling silver.
Because German Silver contains no silver, the material doesn't tarnish but can
get dirty from perspiration and normal wear. You can clean German silver jewelry right at home for virtually no
cost to you. Get a clean toothbrush and gently scrub jewelry with either baking
soda or toothpaste. Rinse and dry with a
soft cloth thoroughly to return your item to its normal shine.