OF THE MINERAL WORK.

commonly contain impure, volatile, iron-like gold, and at the same time mature gold; but few contain sulfurous-copper gold.

Stones which are called Quartzen quartz and Hornstein chert by the Germans, containing pure and corporal gold, even if mixed with silver and copper, can be roasted or burned, crushed, and extracted with Mercurio mercury, and if they abound in gold, smelted with a flux; which labors the diggers and handlers of minerals do not ignore, and of which it is not my intention to write, because others have also written about them long ago. But those flints, Quartzen quartz and Hornstein chert, found almost everywhere, containing at least a little iron-like gold dispersed within them, or marcasitheum marcasite, and that either fixed or volatile, cannot be separated with fruit and profit, namely neither by mercury nor by flux; for which reason they are neglected by the diggers, either out of ignorance or because of intolerable costs. I, however, having tested those rejected stones, however little gold they possess, having found that they can be separated with the greatest profit, I did not wish to omit publishing this excellent science for the benefit of the Christian neighbor, not doubting that this publication will be useful to countless people. For I do not ignore that both the learned and the unlearned, the noble and the ignoble, the secular and the spiritual, have been reduced to poverty by war or otherwise, so that they can barely sustain their family, etc. For the sake of these and other needy persons, I have published this Secret, by which, when properly treated, it will be possible to earn no small amount annually, especially where those stones are had in abundance, as well as that spirit of salt, of which a description is given...