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On Thu, 13 May 2004 17:19:58 GMT, R. Wink
wrote:

A lot of stuff is 14K "filled" which is to say "plated" If this was
plated and wore off, then the base metal is most likely
brass or copper.
R. Wink


Goldfilled is not goldplated. cf: McCreight's Complete Metalsmith
book , et al.

The words "gold filled" are somewhat a misnomer, although well accepted in
the jewelry industry. What would be more appropriate would be filled gold,
meaning that the outer shell is made of gold alloy, which has been affixed
to base metal, either one side or both, then the items fabricated. The
stock is often further processed after the gold layer has been applied,
including rolling to specific thickness before further fabrication.

Gold filled jewelry will usually specify its content with a fraction and the
karat fineness. Old eyeglass frames were so marked (assuming they were
gold frames), with a common marking of 1/10 12K GF, for example. That's
telling you that 1/10 of the mass is 12K gold, or the item was fabricated
with an overall pure gold content of 5%.

In gold, 24 K(arat) is pure, thus one K =4.1666% gold. Marking
regulations allowed for deviations according to manufacturing procedures, so
the items made were usually a half karat lower than the marking, which was
perfectly legal at the time they were made.

If the chain in question is made from karat gold, not gold filled or plated,
a drop of nitric acid would slightly discolor the area where the acid was
applied, turning it a brown color after standing for a few moments. . If
there is a greenish reaction, one that takes place very rapidly, that's a
sure sign that the chain is either plated or gold filled. A chain that has
been worn some time will usually have enough wear to expose the base metal,
which is what the nitric will be dissolving.

Another test for the chain to determine if it is karat gold or gold filled
would be to soak the chain in ammonia over night. Gold filled chains
slowly dissolve away at the core, turning the cleaning solution greenish
blue in the process. Karat gold will tolerate cleaning that way endlessly,
so it's a good way to keep jewelry clean. One must be careful to not soak
pearls or cheap jewelry, however. Only high quality karat gold jewelry
should be so cleaned.

Harold