Franco 10 Pesetas Aluminum

This 10 Pesetas coin, struck from aluminum alloy, weighed a mere 2.52 grams, making it one of the lightest circulating coins in Europe at the time.

That lightness came from a deliberate choice during Spain's economic adjustments under Franco, where the government opted for cheaper materials to stretch resources. Production ran from 1966 to 1975 at the Madrid mint, with designs featuring the national arms on one side and a simplified portrait on the other. Variations in edge lettering or minor die differences keep some collectors mildly amused, though most examples are common enough to find in bulk lots.

Exact mintage figures for certain years remain murky; records from the era weren't always meticulous. As for myths about its durability—it's aluminum, not magic—it wore down quickly in circulation.

Some say it felt like carrying air in your pocket.