High in the Peruvian Andes, archaeologists have discovered a 15th-century 'Inca Bureau of Mineral Assaying.' This administrative outpost served as a quality-control center for the silver extracted from nearby high-altitude mines. The site yielded a rare collection of Quipu records—the Inca's system of knotted strings—which appear to be ledger entries documenting the purity levels and weight of silver ingots destined for the imperial capital of Cusco.
Researchers from the Cusco Archaeology Collective found specialized ceramic testing crucibles and bone-ash blowpipes used in the cupellation process to separate silver from lead and other impurities. The presence of standardized assaying tools at such a remote elevation indicates that the Inca state maintained rigorous industrial standards for the precious metals used in ceremonial objects and elite status symbols.