I have a pair of 900 earrings that are bright yellow, from Asia somewhere, and while one clutchback says 900, the other says 21.6K. Get it tested.
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900 mark by: Anonymous
900 is also platinum, though the color is confusing
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.900 is Coin Silver by: Anonymous
Many European countries mark silver and gold with numerical fineness marks in thousandths, e.g.,
SILVER: 800, 830, 900, 935, etc.
GOLD, 333, 500, 585, 750, 875, etc.
900 was dubbed "COIN SILVER" because coin silver (.900) was the silver standard for coins and lots of silversmiths used to melt the coins to make jewelry & watch cases.
if the color of the metal is gold then they might have been plated in gold. Electroplating was first used in the 1840s.
