In my humble experience, not only are electronic gold testers highly
unreliable, they can be downright dangerous for your reputation as a
Long story short… I design and work in mixed metals. A few years
ago a retail buyer took one of my pieces to a jewelry store to have
the solid 14k gold section tested. The retail buyer was alarmed when
the clerk informed her that the electronic tester had confirmed that
the tested piece was not 14k gold. This was vexing for me as I
understood that the mixed metal composition of the piece would
register differently than a solid gold piece.
To put the question to rest once and for all, I called Rio Grande -
my gold supplier - to test the item with a nitric acid test kit in
the retail buyers presence. The acid test confirmed that the 14k
gold portions of the mixed metal were indeed 14k.
A stiff buff will expose gold plating immediately. If you don’t want
to damage the surface, toss the item on a digital scale. Gold is
considerably heavier than base metal or silver.
“Gold filled”, is just a synonym for extra heavy 12k gold plate, and
the gold is usually applied to the “top” surface only. Often, gold
filled will be plated (“bonded”) atop jewelers brass (or red brass)
which mimics the color of 14k.
A softened treated razor edge wheel loaded with Zam will strip away
the 12k layer in short order. A quick application of an oxidizing
agent like Hilox or Winox will quickly reveal the base metal,
turning it black almost immediately. Carat gold may darken slightly,
but the oxide can be quickly wiped away with a soft cloth.
Electronic gold testers are gimmicks for the uninformed, and
unskilled. My best advice is to avoid them entirely.
M. M. Rogers Design