THE GOLD

Gold During the Transition to Modern Scientific Views

"It is no wonder that, respecting the matter out of which Metals are made, there should be such a variety of opinions among Persons authorized to express them; for it would appear that, by a special Providence, the Author of Nature wished to hide them in the Depth wherein they were created, and in the hard Rocks which enclose them, in order to place some Obstacle to human Ambition. Those who have risen to the rank of Philosopher through the study of Causes, leave on one side the raw material as a very remote Principle of Metals, as it is of all the other corporeal things of the World, and indicate another, also very remote, which is in part, a certain Humid and Unctuous Exhalation, together with a certain portion of viscous and greasy Earth, from the Mixture of which results both Metal and Stones. Thus, if dryness predominates in the Mixture, Stone results; and if it has a greater amount of Greasy Water in it, Metal results: this is maintained by Plato, Aristotle and their followers. From the abundance of this pure, shiny Humidity is derived the Lustre of Metals, in which, among the other elements, Water, as is well known, predominates; and thus they flow and melt under the action of Heat. From the varied Temperament and Force of the matter referred to is derived the Diversity of the metals, of which the purest of all, and Nature's chief effort, is Gold."

Later in his treatise, Barba describes the geological and mineralogical occurrence of gold in many parts of the Cordillera of South America. Of the deposits of the Charcas district of Bolivia he says:

"There is no one who has not heard of Carabaya, which is a Region famous for the abundance and purity of its Gold, its Metal being as fine as the celebrated Gold of Arabia. It is Gold of twenty-three carats and three grains. The quantity, which has been, and is still being extracted, is incredible, although that which has been taken out so far has been found by People who have looked for it only in the Rivers; only now are they commencing to work the many rich Veins. Carabaya is situated alongside of Larecaja, where auriferous Ores abound. In some of the streams in those Parts, Gold is found in the Form and Colour of small lead shot, which, when they have been melted, take the red Colour of Gold, with but little loss through the disappearance of the Crust which covered them when found. The man who discovered the Gold in this form did not know what it was until he was enlightened by a Friend whom I had advised of its true Nature. From Larecaja to Tipuani is a region occupied by savage Indians, the same having been invaded over twenty years ago by an Expedition sent to La Paz, I forming part thereof. There so much Gold is found that the accounts of it would be incredible, were it not for the many Witnesses who have seen it, and vouch for the fact.

The real name of the city of La Paz, Chaquiyapu, which we have corrupted into Chuquiabo, means, in the native language of this Country "Farm" or "Estate" of Gold. Many mine Workings exist there, dating from the time of the Incas. It is a land well known to be fertile in Gold; and, during the rainy Season boys find Nuggets in the Streets, especially in that one which descends by the Monastery of the Dominicans towards the river. In Coroyco, and other parts of the Andes of Chuquiabo, there is Gold also in many ravines, grey on the outside like Lead."

Finally, Barba gives many practical hints on how and where to prospect for gold veins; for instance:

"There is no sure or infallible rule which, without further experiment or examination, will enable the particular kind of metal contained in a hill to be determined simply by the Colour of the earth on the surface. And thus, although the material in which Gold is found is most frequently Red or dark Yellow, like to brick which has been very much burnt, veins thereof are frequently found in white Calichal (White Earth, Kaolin) as in Oruro and Chayanta."

Anyone who has seen the primary, and in places supergene, white and yellow (clay mineral, alunitic, and propylitic) alteration and the supergene red (limonitic) and yellow (arositic) oxidation products associated with (Tertiary) gold deposits will recognize instantly the value of these guides.

Late in the seventeenth century John Woodward (1665-1728), the English physician, antiquarian, and collector of fossils, sought to explain the features of the globe in terms of a flood (the universal Deluge) released through fractures (perpendicular intervals) from inside the earth in An Essay Toward a Natural History of the earth and Terrestrial Bodies, Especially Minerals (1695) and later in The Natural History of the Earth, Illustrated, Inlarged, and defended (1726). In that second work, concerning the origin of mineral veins he states:

"Water takes up the particles of metall, which lay before loose, and separate, in the interstices, and pores of the strata of stone, and thence carries them into the perpendicular fissures of the strata."

Later Pryce (1778), after examining various theories of origin, explained the tin veins of Cornwall in the following way:

"From this we may reasonably infer, that water, in its passage through the earth to the principal fissures, imbibes, together with the natural acids and salts, the mineral and metallick particles, with which the different strata are impregnated; and meeting, in those fissures, matters which have nearer affinities with the acid, of course disengages it, in whole or in part, from the metallick and mineral particles, which it had held dissolved; and which, on being so disengaged, by the natural attraction between its parts, forms different ores, more or less homogeneous, and more or less rich, according to the different mixtures, which the acid had held dissolved, and the nidus in which it is deposited. The acid, now impregnated with a new matter, passes on; till meeting with some other convenient nidus, it lodges in that, and thereby acquires a fresh impregnation, perhaps at last totally unmetallick; or, for want of meeting with a proper nidus, appears at the surface, weakly or strongly tinctured with those principles it had last imbibed."

These are clearly statements of the lateral secretion theory; they differ only in detail from the theory postulated by Agricola. Nils Steensen (Nicholas Steno) (1638-1686), the Danish physician and theologian, likewise espoused a lateral secretion theory. In his De solido intra solidum naturaliter contento dissertationis prodromus (1669) he disputed the Vulgar opinion and the Aristotelian and alchemical notions about the origin of veins at Creation and hypothesized that uplifting earth movements created clefts, fissures, and interstices within the rocks in which mineral matter from the rocks was precipitated. To quote Steno:

"It is more than probable that all those minerals which fill either the clefts or expanded spaces of rocks had as their matter the vapour forced from the rocks themselves... " (Winter, Hobbs, and White, 1968).

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Gold in: Gold 1 2 Primitive Classic Medieval Renaissance post-Renaissance period.
Gold: Deposits Transport

Rafal Swiecki, geological engineer email contact
February, 2008

This document is in the public domain.