Tungsten As A Filler For Gold Coins

Aye, Tungsten has been used quite often as a filler for faux poured bars for a long time now. XRF will not detect it as XRF bounces off of the surface of the coin, and doesn't penetrate it.

Using it to make bogus *coins*, however, would pose some challenges. As bioemist6 mentioned, it's too blasted hard to strike. Theoretically speaking, one *could* make a gold-tungsten-gold laminated "sandwich," much like modern dimes, quarters, and halves with cupronickel-copper-cupronickel.

Because of the difference in hardness, though, you'd probably have lots of problems with the lamination separating when they're struck. If you were to get it right, however, all you'd need to do is gold-plate the edges and it'd be very hard to discern from an all-gold coin.

Scary stuff.

That would be difficult to test non-destructively.

You could drill a hole in it; tungsten would not only be harder to drill through but a different colour. You could also try to melt it down. Tungsten won't melt at gold-refining temperatures. Tungsten is much harder than gold, so the old "bite test" or it's more scientific mechanical equivalent, the macroindentation hardness test, would also work, but could be fooled if the gold layer around the tungsten core were particularly thick.

Of course, if you do any of these things, it'd be a little late at that point to ask for a refund.


Most of the tungsten mining and refining these days is happening in China, which is why they're always mentioned as the suspects in these gold switch-out theories.