Casa de Moneda de Potosí

• City: Potosí, Bolivia
• Mint mark: P
• Years active: 1574–1825
• Metals: Silver, Gold (limited)
• Assayers: B Baltasar Ramos Narváez; L / RL Juan de la Rynaga Salazar; C Cristóbal de Balbas; A López de Barriales; B Juan Ballesteros Narváez; R Juan Alonso Rodríguez de Baeza; T Juan Ximénez de Tapia; TR Tapia / Rodríguez (transitional); P Francisco de la Peña; E Antonio de Ergueta; V Pedro de Villar; VR Villar / Rodríguez; F José de Matienzo y Fernández; CH Cristóbal de Heras; Y José de Lizarazu; q Luis Aldavez de Quiñones; V Agustín de la Vega; JR Juan de Rodríguez; PR Pedro de Recavarren; PP Pedro Pablo de Arana; PJ Pedro José de Sanjines

The largest silver mint in human history, fueled by the legendary Cerro Rico — the "Rich Mountain" that bankrolled the Spanish Empire for over two centuries.

History

Potosí was not just a mint — it was the engine of the Spanish Empire. Perched at 13,000 feet in the Bolivian Andes, the city sprang into existence after the discovery of Cerro Rico in 1545, a mountain so rich in silver that it seemed inexhaustible. By the early 1600s, Potosí was one of the largest cities in the world, rivaling London and Paris in population. The Casa de Moneda — the Royal Mint — was established in 1574 to convert raw silver into coinage on-site, eliminating the dangerous and costly process of shipping raw ore across the Atlantic. The mint operated water-powered stamping mills and employed hundreds of indigenous workers under the brutal mita labor system. Potosí cobs are among the most commonly found coins on Spanish colonial shipwrecks. Their distinctive "P" mint mark and often crude, hand-struck designs make them instantly recognizable to collectors. The earlier cobs (pre-1650) tend to be irregularly shaped with partial strikes, while later pieces show improving quality as the mint's techniques evolved. The sheer volume of silver that flowed from Potosí is almost incomprehensible. Scholarly estimates credit the Potosí district with roughly 61% of the silver produced in southern Spanish America between 1545 and 1810, and at its peak — roughly 1580 to 1630 — the mountain is estimated to have supplied as much as 60% of global silver production. The coins minted here traveled to every corner of the globe — from the markets of Manila to the banks of Amsterdam. The mint continued operating through Bolivian independence in 1825, but the glory days ended long before. By the late 1700s, the mountain's veins were thinning, and the city that once held 160,000 people began its long decline. Today, the mint building still stands as a museum — a monument to the mountain that changed the world.

Notable features

• Highest-altitude mint in the world at 13,000 feet
• Largest single source of silver coinage in history
• Transition from cob to milled coinage beginning in 1767
• Famous Pillars & Waves design on early cobs

Coin types

• Silver
• Gold
• Silver
• Silver

Monarch periods

• Philip II — First coins struck at Potosí. Established the mint to process Cerro Rico silver locally.
• Philip III — Continued high-volume cob production. Period of peak silver output from the mountain.
• Philip IV — The Great Potosí Mint Fraud came to light in 1649: royal assays showed cobs holding far less silver than the 93/100 fineness decreed in 1642. Visitador Francisco de Nestares Marín's investigation led to the execution of Francisco Gómez de la Rocha, and a 1649–1652 reform included countermarking existing coins and a redesigned cob type.
• Charles II — Pillar-and-waves design adopted for cob coinage. Quality improved after the debasement scandal.
• Philip V — First Bourbon king. Long reign saw continued cob production with updated shield designs.
• Ferdinand VI — Brief reign with modest output. Cob coinage continues in traditional style.
• Charles III — Historic transition from cob to milled coinage at Potosí. Pillar type (1767–1770), then bust type.
• Charles IV — Full bust-type milled coinage. Declining silver production as the mountain's veins thinned.
• Ferdinand VII — Final monarchical coinage. Mint continued striking through Bolivian independence in 1825.