Rare 1647–1648 Spanish Colonial Silver 8 Reales Cob Potosi Philip IV

This Rare 1647–1648 Spanish Colonial Silver 8 Reales Cob, struck at the Potosí Mint in Bolivia under King Philip IV, is an extraordinary survivor of one of the most turbulent periods in Spanish colonial coinage. Weighing 28.06 g and measuring 38 mm, this irregularly shaped cob is a remarkable artifact of the 17th-century Spanish Empire.

The assayer’s mark on this piece is weakly struck, making precise attribution difficult. It could correspond to assayer “T” (Pedro Treviño), “Z” (Antonio de Zincón), or possibly the rare overmark “T/Z”, noted in advanced references. Confirmation of the 1647–1648 issue comes from the lion and castle design details, characteristic of this period, and the distinctive use of a small “o” over “o” in the numeral “8.”

This coin is particularly scarce, as most 8 Reales of this issue were later confiscated, counter-stamped, or melted during the aftermath of the infamous Potosí Mint Scandal of 1649. That scandal, caused by widespread fraud and debasement at the Potosí mint, led to mass recalls and destruction of coins, making surviving specimens like this especially rare and valuable.

The obverse carries the Jerusalem cross with lions and castles in the quadrants, while the reverse displays the crowned Habsburg shield, incorporating castles, lions, the pomegranate of Granada, and the iconic Pillars of Hercules. Struck by hand on an irregular planchet, this cob exhibits the individuality and authenticity of early colonial minting.

For collectors of Spanish colonial coinage, shipwreck-era silver, and rare assayer varieties, this coin is a true piece of history—combining rarity, controversy, and global significance in one remarkable specimen.