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Material World
Place

Potosí

One mountain of silver financed an empire, at a human cost that is still being counted.

A city in Bolivia at four thousand metres, beneath Cerro Rico — a mountain whose silver deposits were the richest ever worked. Silver was mined here from 1545, and for a century Potosí was among the largest cities in the world.

The metallurgy that made it possible was the patio process from 1554, which extracted silver by amalgamation with mercury rather than by smelting. That removed the fuel constraint at an altitude where there is no wood, and created a mercury demand supplied from Huancavelica in Peru and Almadén in Spain.

History

Worked under the mita, a system of forced Indigenous labour adapted from an Inca institution and applied at a scale and mortality that has no defensible comparison. The death toll over the colonial period is disputed and is counted in hundreds of thousands at the low end.

Spanish silver from Potosí and Mexico entered global circulation on a scale that moved prices across Europe and Asia, and a substantial share of it ended up in China, which was monetising silver at the time.

Economic significance

It is the case that connects a material, a metallurgical process and a global economy most directly, and the one where the cost is least possible to leave out of the account. The mountain is still worked by cooperatives under conditions that remain dangerous, and Cerro Rico is subsiding.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

produces

  • Silver element · from 1545, by amalgamation with mercury after 1554, at a scale that moved prices across Europe and Asia

Sources

  • Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)
  • Material World
    Our own writing

Where it comes from, and what it becomes

Follow Potosí back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

  • Potosí → produces (from 1545, by amalgamation with mercury after 1554, at a scale that moved prices across Europe and Asia) → Silver → is sourced from (from the anode slimes of copper electrorefining, the same stream the platinum group and the tellurium come out of) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation
  • Potosí → produces (from 1545, by amalgamation with mercury after 1554, at a scale that moved prices across Europe and Asia) → Silver → is sourced from (from the anode slimes of copper electrorefining, the same stream the platinum group and the tellurium come out of) → Copper → is extracted from (the principal copper ore worldwide) → Chalcopyrite
  • Potosí → produces (from 1545, by amalgamation with mercury after 1554, at a scale that moved prices across Europe and Asia) → Silver → is sourced from (from the anode slimes of copper electrorefining, the same stream the platinum group and the tellurium come out of) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (roasted to drive off sulfur, then reduced to copper) → Chalcopyrite
  • Potosí → produces (from 1545, by amalgamation with mercury after 1554, at a scale that moved prices across Europe and Asia) → Silver → is sourced from (from the anode slimes of copper electrorefining, the same stream the platinum group and the tellurium come out of) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (reduced with carbon to metallic tin) → Cassiterite
  • Potosí → produces (from 1545, by amalgamation with mercury after 1554, at a scale that moved prices across Europe and Asia) → Silver → is sourced from (from the anode slimes of copper electrorefining, the same stream the platinum group and the tellurium come out of) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (reduced with coke in a blast furnace) → Hematite
  • Potosí → produces (from 1545, by amalgamation with mercury after 1554, at a scale that moved prices across Europe and Asia) → Silver → is sourced from (from the anode slimes of copper electrorefining, the same stream the platinum group and the tellurium come out of) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (the phosphate rock charged to the electric furnace, with coke to reduce it and silica to take up the calcium) → Apatite

These are the most distinct paths back. Potosí can be traced through others besides.