Molybdochalkos

Molybdochalkos (Greek: Χαλκομόλυβδος,^[1] "copper-lead") is an alloy of copper and lead. It was the typical base metal used in the kerotakis, an alchemical invention credited to Mary the Jewess.

In Mary's writings, the "blackened lead" formed by exposing the alloy to sulfur vapors was considered an artificial decomposition, entirely separate from naturally black lead. This would form a basis for the alchemical process of blackening that would later be named nigredo.^[2]

References

1. Liddell, Henry George; Scott, Robert (1940). A Greek-English Lexicon (9th ed.). Oxford University Press. ISBN 9780198642268.
2. Kyle Fraser (2018). "Distilling Nature's Secrets: The Sacred Art of Alchemy". In Keyser, Paul; Scarborough, John (eds.). The Oxford Handbook of Science and Medicine in the Classical World. Oxford University Press. pp. 732–733. ISBN 9780199734146.