Opponents of fiat money are often found looking whimsically to the past, longing for the days of commodity-backed money, particularly the gold standard. But why is gold so valuable? Is it a matter of perception? Could people not just as easily have decided that Boron would be the most valuable element? Greg Mankiw posted a great (4 minute) clip from NPR's Planet Money, which looked at this question through the lens of chemistry.