Gold isn’t the only precious metal, or even the most expensive. That “honor” belongs to rhodium, whose price far exceeds that of its weight in $100 bills. There’s an interesting coincidence in this price range: Cocaine is about $50/gram, while a fifty dollar bill weighs about a gram. Even exchange? Platinum is also in the same price range, so you could say that $50 bills are worth their weight in platinum.
The Monetary Density of Things