XVI. But of the Green Lyon of Fools, this we say, that from it with a strong fire is drawn Aquafortis, in the which, the aforesaid Philosophers’ Lyon of the Mineral Stone, ought to be Elixirated, and assumes its Name. Raymundus saith, it were better, or safer, to eat the Eyes of a Basilisk, than that Gold, which is made with the Fire against Nature.
XVII. And I say also, that the things from whence the same Aquafortis is drawn is green Vitriol and Azoth: i.e., Vitriol Natural, not Artificial, viz. the droppings of Copper, called also Roman Vitriol, Roman Gold, by many of the Philosophers, from the abundance of its noble Tincture, the which Tincture must be fermented with common Gold.
George Ripley – Medulla Alchymiae