more nerd than you can shake a stick at

[rone]

I did a little math today.  Take the Greyhawk gold piece, which is depicted in the Dungeons & Dragons v3.5 Player's Handbook as having the same size as a half-dollar piece (diameter of 30.61 mm), and is listed as weighing one fiftieth of a pound (9.012 g).  If you assume it is 100% gold, that gives a thickness of 0.639 mm, or less than half the thickness of a dime.  Not quite foil-thin, but i suspect that it would lead to a lot of crumpled coins, and trying to mint something that thin is probably not very practical.

My only comfort is that some nerd somewhere figured this out as soon as the book came out, and sent Wizards of the Coast a nastygram about it.