If you create a 100 gramm copper bar and plate it with gold, its still able to identify it. Because copper got a different density.
Of course, this is why I wrote "alloy".Gold is 19320 kg/m3
Tungsten is 19600 kg/m3
So mixing Tungsten ($100+/kg) and a little of a lighter metal can produce an alloy with the exact same density as gold. Once plated with gold I don't know how to tell the difference. My question was : does anyone here know?
to technical. For gold and silver, take it to a real world PM shop and have it tested using acid (aqua fortis).
As for gold plated tungsten, that is hard but not impossible to detect, using either a drill or if you want non-destructive test, put a variable wave sine through it, tungsten and gold don't react the same. Same with ultrasonics.
There are many stories (urban legends) about this stuff, it only makes economical sense to fake larger size ingots. The only exception I've ever seen is the Chinese Panda coins but then again, most stuff coming from China is tainted ;-)
PS: You can fake siver with molybdenum as well
http://www.zerohedge.com/news/tungsten-filled-1-kilo-gold-bar-found-uk
https://www.youtube.com/watch?v=5FvM_4B7Pkc
