Calid equated sulphur with the 'form' and argent vive with the 'matter' of metals: 'all Metals are compounded of Mercury and Sulphur, Matter and Form; Mercury is the Matter, and Sulphur is the Form'
This passage establishes argent vive's foundational doctrinal role as the material principle of metals, counterposed to sulphur as formal principle, and identifies its symbolic avatar as the dragon.
, A Dictionary of Alchemical Imagery, 1998thesis