LIV. How, out of poor Mines of Copper, from which no profit can be perceived, Copper, as also Gold it self if it be present, is to be easily and without costs, extracted and separated.
The sandy or sulphurous Mine or Mineral of Copper is to be roasted or calcined, by burning even to the consuming of the Sulphur, because sharp waters do not assault sulphureous matters, the Mineral being calcined and beaten into a powder, fill a gourd, and pour our solving secret on the same, the which I have taught above at the extracting of Minerals.
The whole dissolvent in abstracting or distilling is recovered, and that indeed not without increase. But the Copper and Silver do stick fast in the dissolved Salt, which remained in the Mineral after the abstraction, and the which is to be washed out with water, out of which water, which drew out that Salt, the Gold contained therein, may by the solution of Lead or Silver, be drawn forth.
But if the same water be boiled untill a thin skin appear at the top, and exposed to the cold, it will shoot into a green vitriol, but for the extracting the Copper out of the Salt-Water, Rods of Iron are to be put therein, which do attract the Copper, the which being withdrawn and washed clean, and melted into Copper by fusion, is administred for other uses: For because it is like to a tender and filed powder, it is changed by an easie business into Verdi-grease, after the manner which shall by and by be taught.
LV. After what manner Gold may by an easie business by Fire and Salt, be separated out of Copper.
If Gold shall be mixed with a mass or lump of Copper, all the Copper is to be reduced in a bright burning Fire into Ashes: and the Ashes are to be infused in our secret Aceum or Vinegar, the which dissolveth the Copper onely by decoction, and leaveth the Gold undissolved, like a shining powder, to be dried and melted with Borace, out of which Gold of twenty three Caracts proceedeth.
That Vinegar, our secret Aceum, draws all the Copper from the golden Calx. The Copper is separated from the Vinegar by Rods of Iron, being laid therein as we have taught in the foregoing manner.
LVI. How Copper being extracted out of vitriolated Water, and adhering to Rods of Iron, is to be changed into Verdi-grease.
This pure Copper may be moistened with the strongest Vinegar, and put into earthen Pots, the which being covered with its Cover well fenced with Clay, are to be placed in Horse dung, and to be left therein for a time, yet so as that the heap of Dung be sometimes renewed. All the Copper is in a short time changed into Verdi-grease, and indeed far more pure than that which is set forth to Sale in the Shops, and which is made in Spain, by the husks or pressed out of clusters of Grapes.
N. B. In extracting Copper out of Mines, regard is to be had unto this thing, to wit, that with poor and wild or course veins of Copper, Lapis Calaminaris, or Zink is sometimes found to be admixed; which is no ways perceived to be in them. But if those Minerals are extracted with Aq. Regis, and this be to be taken away by Distillation, none of the Aq. Regis goes forth, but onely a flegm without savour, because the Lapis Calaminaris or Zink doth retain all the Acrimony with it, just as if those two Minerals should say to the Aq. Regis, we do not as yet let thee go, because as yet, we have need of thy indeavour for our amendment, &c.