50 Dollars - Hassanal Bolkiah Sultan's 50th Birthday

Hassanal Bolkiah turned fifty in 1996 as one of the wealthiest heads of state on earth, with Brunei's oil revenues having made him, by some estimates of the period, the richest individual in the world. The birthday celebration was characteristically extravagant — the official festivities reportedly cost in excess of $16 million.

The .917 fineness places this squarely in the 22-karat crown gold tradition, the same standard used for British sovereigns. At 31.10 grams, the specification mirrors a troy ounce, a deliberate choice for a state acutely conscious of commodity benchmarking.