Carlos IV 8 Reales

The Carlos IV 8 Reales, struck in American mints like Mexico City and Potosí, was minted from silver mined in the Andes, fueling Spain's global trade empire. That silver, often impure and refined on site, made these coins a cornerstone of 18th-century commerce.

Design-wise, the obverse shows Charles IV's profile, complete with that characteristic Habsburg jaw, while the reverse features the Pillars of Hercules. Variations exist due to different assayers; some years bear the mark of a particularly sloppy engraver, whose errors now fetch premiums.

Mintage figures are murky for many dates, as records burned in colonial upheavals. Still, survivors turn up in odd places, from shipwrecks to attic finds.

One assayer's die must have been off; the coins sometimes look like Charles is smirking.