I know this is an older post but as I worked at pawn shops in the past, thought I'd share. Most of this is in
reference to testing jewelry... but the same generally holds true for raw gold.
How we checked it was to (assuming scrap item) file a small area to get past any plate. Then a small drop
of nitric acid on the spot would produce a reddish-brown color. One tended to get used to the variances of
color to know what karat it was. On nice items we would rub the item on a scratch stone. Then you take a
gold needle (whatever karat the customers item was marked) and scratch this on the stone as well. A drop
of nitric acid on both marks and one should see the same color. Truth is, after a few years of working with
gold you learn a certain "feel" to real gold. They (crooks) are always trying something new, but you tend to
have an instinct for the real deal. Note, a lot of chains are also coated with rhodium (for shine) so a drop
of acid on an unfiled area may give incorrect results.
These days I have the acid on hand as I enjoy the occassional foray into gold prospecting/panning and also
like to check old rings I dig up. Acid/test kits can be had off the Internet.
They now have electronic gold testers, but I'm old school and don't really trust them (I've seen one call some
scrap material from a computer mfg company 18KT and it was gold colored trash... probably read the plating).
Hope someone finds this useful! Linkback:
You are not allowed to view links.
Please Register or Login