Ferdinand VI 4 Escudos

Ferdinand VI's 4 Escudos were struck from gold sourced largely from Spanish American colonies, a direct link to the empire's economic backbone during his reign.

That gold, typically 22 karats fine, arrived in Spain via galleons that dodged pirates and storms, only to be melted down in Madrid's royal mint. The obverse shows the king's bust, facing right, with his name and titles squeezed around the edge; the reverse features the Spanish coat of arms, complete with the Pillars of Hercules. No fancy legends, just the facts etched in.

Mintage figures? They're murky at best—many records burned in the 1830s upheavals. Historians guess thousands were produced yearly, but that's just a hunch.

Some collectors swear these coins bring good luck, but that's nonsense; they're merely heavy in the hand, like any other lump of history.