And there's nothing illegal about mailing gold to people. I've purchased jewelry online.
Except for the small detail that if it goes "missing," the UPU members all say you have exactly zero comeback. Missing includes games of parcel football, sticky fingers and outright failure to deliver. Sending precious metals through a postal system is about as secure as leaving it on the street.
Also, I now have a mental picture of Mr Shouty walking around like a 7 stone adenoidal Mr T replete with sovereign rings, capped teeth and many bling chains and I cannot unsee that which my mind's eye hast beheld. Please pass the mind bleach.