10 Dollars - Elizabeth II The Stony Bridge

Part of the miniature gold "Bridges of the World" series produced for the Solomon Islands by a European mint-on-demand operation, this piece carries nominal legal tender status under an arrangement that has nothing to do with domestic monetary policy. The Solomon Islands has issued dozens of such collector coins annually since the early 2000s — a licensing arrangement that generates modest revenue while the country itself circulates only base-metal coinage.

At 0.622g, the gold content is fractional almost to the point of tokenism — roughly one-fiftieth of a troy ounce.