quicksilver (n.)

common popular designation of metallic mercury, Middle English quik-silver, from late Old English cwicseolfor, literally "living silver," so called for its mobility, translating Latin argentum vivum (source also of Italian argento vivo), "living silver;" so called from its liquid mobility. See quick (adj.) + silver (n.). Similar formation in Dutch kwikzilver, Old High German quecsilbar, German quecksilber, French vif-argent, Italian argenta viva.