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Gold During the Renaissance
We see in this account of the origin of ores a somewhat muddled version of the views of the Aristotelians, the alchemists, and the astrologers. Reading further in the Bergbiichlein we learn about methods of prospecting for veins, and in the fifth chapter we have an exposition on gold ore. From the translation of Sisco and Smith (1949, p. 39) we read:
On Gold Ore
"Gold, however, according to the opinion of the philosophers, is made from the very finest sulfur -so thoroughly purified and refined in the earth through the influence of Heaven, especially the Sun, that no fattiness is retained in it that might be consumed or burnt by fire, nor any volatile, watery moisture that might be vaporized by fire-and from the most persistent quicksilver, so perfectly refined that the pure sulfur is not impeded in its influence on it and can thus penetrate and color it from the outside to its very core with its persistent shade of citrine. And thus the two, sulfur and quicksilver, being the mineral matter, are joined into a metallic body in the most powerful and enduring union through the influence of Heaven, delegated to the Sun, and through the fitness of the location, through which the mineral exhalations of sulfur and quicksilver wind and drive and break their way. And such union cannot be dissolved even by the most violent and most powerful effort of fire.
Gold occurs in different ways. Some, in ordinary river sand, some under the overburden near swamps, some in pyritic deposits, some, as the native metal, in stringers and veins, and some in various ores and alteration products contained in veins and stringers, whether these are schists, or black, brown, grey, blue, or yellow alteration products, or clayey ores. The gold generated in river sand is the purest and most exalted kind because its matter is most thoroughly refined by the flow and counter-flow of the water and also because of the characteristics of the location where such gold is found, that is, the orientation of the river in which such placer gold is made. The most suitable location for a river is one between mountains in the north and a plain in the south or west. And the most suitable direction of the current is from east to west. The next best is from west to east, with mountains located as described before. The third best is from north to south, with mountains in the east. But the worst, as far as the generation of gold is concerned, is from south to north if high mountains rise in the west. The possible directions of the flow of water are as manifold according to the quarters of the earth, as those of the strike of veins, which was described earlier in the chapter on silver ores. And each direction is judged better or worse in the measure as it approaches or deviates from what has been said above.
The better to recognize such locations and streams that carry gold, it should be remembered that in general gold is likely to be born in streams in which precious stones are found, such as amethysts, rubies, rock crystals, and other highly refined pebbles, which are an indication of the fitness of the place. According to the opinion of Albertus Magnus, hot and dry fumes or exhalations are seldom extracted from the earth without being accompanied by warm, moist vapours. The gemstones are wrought and born of dry fumes; and the clearer, finer, and nobler the fumes are, the more beautiful and the better and harder will be the gems. Metals are wrought and made from moist vapours, and how strong and good the metal is will depend on how clear, pure, and well-digested the matter is from which the vapours or mists are extracted. Since moist and dry exhalations rise together, but each is hardened according to its own nature, it is a very reliable indication of the occurrence of gold, as said before, if precious stones are found in a river. Also, where you find in a river or nearby little crystals of tourmaline of a dense, fine structure a gold occurrence is not far off. It is, however, essential that the crystals be very fine because where the coarse kind is found, there is little hope for an occurrence of the best and finest of the metals, the gold. The value and actual gold content of the gold that is generated under the overburden near swamps depends on how much of the grey or black imagnetitel sand that together with the little leaves or grains of gold constitutes the schlich is mixed up with it in smelting. In many places this schlich contains more silver than gold, and sometimes even copper, so that the gold is less valuable wall stringers that contain native gold leave a vein either sideward or downward, it is advisable to explore for other veins; by such foresight the stringers and the veins may be worked together."
Disregarding some rather fanciful ideas such as the influence of Heaven, we have in this description a relatively modern account of the occurrence of gold. Calbus credits Albertus Magnus with some of the ideas in his narrative and follows him in considering that alluvial gold accretes in situ in streams. The reference to the association of tourmaline, especially the very fine crystalline type as opposed to the coarse crystalline variety, is remarkable because I have found this fact to be true in many auriferous deposits personally investigated.
Vannoccio Biringuccio (1480-1539), metallurgist, master founder, and munitions advisor to the Petruccis of Siena and to Pope Paul III in Rome wrote the Pirotechnia, probably in 1538, and it was published in 1540, the year following his death. The work consists of ten books, most of which are concerned with metallurgy, pottery, and munitions. In the preface to the first book a guide to prospecting, developing, and mining mineral deposits is outlined, and in the first chapter, entitled, "Concerning the Ore of Gold and its Qualities in Detail", we read from the abbreviated translation of Smith and Gnudi (1959, p. 28) the following:
And speaking thus of this precious metal I believe that it is certain that it is and can be generated in all those places where the heavens influence the elemental dispositions and causes. And here wishing particularly to tell you what I have heard concerning this, I say that through admixture with silver. This sand may also contain an impurity, which darkens the noble and exalted colour of the gold so that it gives the impression of being low-grade gold. In reality this subtracts only a little from its value since by some minor deft manipulation such impurity can be removed from the gold to restore its exalted colour.
Rafal Swiecki, geological engineer email contact
This document is in the public domain.