Obs. Also c(h)alcanthus, calcanth. [a. F. calcante (Cotgr.), and L. c(h)alcanthum, -us, a. Gr. χάλκανθον, χάλκανθος ‘a solution of blue vitriol used for ink and blacking,’ f. χαλκός copper + ἄνθος a flower.]
An old name for blue vitriol (sulphate of copper), and for a kind of ink made therefrom; sometimes also applied to green vitriol (sulphate of iron).
1678. Phillips, Calcanth, a Chymical word, being the same as Vitriol.
1730–6. Bailey (folio), Calcanthum, vitriol rubified. Chalcanthum, vitriol or copperas.
1717. Berkeley, in Fraser, Life & Lett., 586. A vapour sulphurous with some tincture of nitre, calcanthus, and bitumen.
1718. Quincy, Compl. Disp., 14/1. Vitriol, when all its Moisture is dry’d away, becomes Chalcanthum.
