Silver

Spanish Silver Dollar (Piece of Eight)

Spanish colonial mints employed screw presses and hand-striking techniques. The piece of eight featured the Spanish coat of arms obverse and the Pillars of Hercules reverse. Quality control remained inconsistent; weight and fineness varied by mint and decade. Counterfeiting was endemic, driving merchants to weigh and assay all transactions.

Spanish America's silver wealth—extracted from Potosí's mountain (1545–1825) and Mexican mines—underwrote European commerce and warfare. Between 1650 and 1725, Spain shipped approximately 500 tons of silver annually across the Atlantic. Pirate attacks on treasure fleets (flotas) between 1680 and 1720 captured an estimated 15–20 million pesos, destabilizing Spanish finances and enriching Caribbean privateers and merchant-pirates.

Silver was the only commodity with universal acceptance across Europe, Asia, and the Americas. European mints could not produce sufficient specie; Spanish colonial output filled the void. Pieces of eight became the de facto global currency, enabling long-distance trade in textiles, spices, and enslaved people. Pirates targeted it because it required no conversion, no buyer, and no explanation.

Merchants, ship captains, and port officials conducted all major transactions in silver coin or bullion. Smaller denominations (reales, tomines) served retail trade. Pieces of eight were bitten, weighed, and assayed at every transaction to verify fineness. Pirate crews divided plunder by shares; a common sailor's share might yield 100–200 pieces of eight per successful raid.

Treasure fleet commanders (capitanes generales) reported to the Spanish Crown. Mint masters in Mexico City, Potosí, and Lima oversaw production. Assayers verified fineness. Pirate captains (Blackbeard, Henry Morgan, Captain Kidd) and their quartermasters managed division of silver plunder according to articles of agreement signed before each voyage.

Silver ore from Potosí (altitude 4,090 m) was crushed, roasted, and amalgamated with mercury in massive vats. Refined silver was cast into ingots, then transported to coastal mints. Minters melted ingots, added copper alloy (7%), struck blanks between dies under screw presses, and stamped denomination and mint mark. Each coin required two hammer strikes.

Mexican silver (8 reales, 1 real, ½ real) dominated Caribbean circulation. Peruvian coins from Lima mint were slightly lighter. Potosí coins carried the P-S mint mark and were prized for consistency. Cob dollars—roughly struck, irregular coins—circulated alongside more uniform milled pieces after 1680. Counterfeits using base metal cores were common.

Underwater excavations off Florida (1715 fleet wrecks) and Caribbean shipwrecks have recovered thousands of pieces of eight, ingots, and cobs. The wreck of the Nuestra Señora de Atocha (sunk 1622, salvaged 1985–present) yielded over 200,000 silver coins and 75 tons of bullion. Potosí mint records (Archivo de Indias, Seville) document annual production figures and assay results.