The Collaborative International Dictionary
Porporino
Porporino \Por`po*ri"no\, n. [It.]
A composition of quicksilver, tin, and sulphur, forming a
yellow powder, sometimes used by medi[ae]val artists, for the
sake of economy, instead of gold.
--Fairholt.
Wiktionary
porporino
n. A composition of mercury, tin, and sulphur, forming a yellow powder, sometimes used by mediaeval artists as a cheaper alternative to gold.