Hi All - I have a question on the 10K & 14K solutions for testing
Gold. When you make the mark on the 10K and it stays for quite some
time - but eventually fades, does that mean it’s absolutely not gold,
or is there such a thing that it could be less than 10K? I don’t mean
to get off our path but, I recently bought an antique miniature sword
or knife & leather sheath from the 50’s (3 1/2 inches long) for a
Christmas gift for my brother. It was pitch black and until I put on
my jewelers glasses, (can’t see a thing) I didn’t notice it had - a
horses head, (or dog?) on the end; two types of stones that look like
opal (or could be plastic?) riveted on the sides; and after I decided
to rub it very hard, found it to have a shiny gold underneath! Has
anyone heard of collectibles from the 50’s made with gold or would
this be brass? It looks like gold, looks pitted, but I’m no expert
on this. Would appreciate any help. Thanks Donna
Hello Donna,
I assume you are testing with acids. If a mark stays a wile (10
minutes or more) it means that the amount of gold is a approximately
the contains you tested. But maybe your object is gold plated, you
should grind of a bit and scratch with the deeper laying metal on you
testing stone. The best way is, if you have 9 or 10K gold from who you
are sure about it contains of gold. Make near the mark of your sword,
a mark with this gold. And stripe the acid over both marks, and see
what happens. If you test for example 14K gold. Take 18 K solution, it
fades away while you add the acid on. If you take a 14K solution it
will normally not fade away, or after a long period, (10 or more
minutes.) The amount of acid you have put on the mark can make this
small difference. Also there are small differences between several
marks of testing solutions. You should stay with one type, and learn
how it reacts with different types of gold. But be aware, There is one
thing I have come about, that is, that there are some brass coloured
alloys who will not be affected with 18 K and 20, and 22 K solutions.
You can easily think this is gold. But if you have doubt about what
they give you to test. Try an 8K or 9K solution, this contains also
some HCL. and if it is not gold, the mark will fade away.
Martin Niemeijer