20 g of AU is about 1 cm^3, and in any case still just 20 g. That’s not much of a pommel for a sword. Perhaps a dagger at most - or, more likely, something else entirely.
Seriously - someone thought that a 20 g weight would make a viable sword pommel?
Presumably it was just the outer layer. As one of the goldbugs around here once said, gold foil can be about 1/1000th of an inch thin.