In Classical Times knowledge of minerals was based almost entirely upon philosophical speculations. Interesting theories were never tested by direct observations and mining was not a socially acceptable occupation. Little attention was given to mining and minerals, other than gems, and then only as an adjunct to the broader theories concerning the origin of the Universe.
Although there may have been earlier writers Aristotle is the first known to us to have presented a comprehensive theory of the origin and nature of minerals. In his Meteorologica he advanced the theory that all natural substances consisted of four properties, dryness, dampness, heat and cold, and these were combined in the four primitive elements, water, air, earth and fire, elements that could be transmuted by altering the relative proportions of the properties.
This concept dominated the thinking of man for the next two thousand years. Another early treatise on minerals was De Mineralibus by Theophrastus, a contemporary of Aristotle. Theophrastus accepted the theory of four primitive elements and separated mineral substances into two classes, those affected by heat and those not affected.
The next important work on minerals was the monumental Natural History of Pliny, an encyclopedia of the entire field of Nature, written in 77 A.D. In it are collected all the theories, fables and observations of Greek, Latin and Oriental writers up to that time. This work served as the authority and source book for writers on Natural History subjects for sixteen centuries, although it did not dominate or shape the thinking of men as did the works and teachings of Aristotle.
There was no important work on mineralogy from the time of Pliny until Agricola published his De Natura Fossilium in 1546 and the shorter introductory work Bermannus in 1530. During the intervening fourteen centuries that spanned the rise and fall of the Roman Empire and the Dark and Middle Ages, writers on mineralogical subjects merely elaborated on the information and much of the misinformation contained in Pliny’s Natural History.
The development of mineralogy, if it could be called development, can be traced through the numerous lapidaries and encyclopedias that began to appear after the time of Pliny. There was no factual foundation to this development. Each writer cited some previous writer as his authority for the most ridiculous and incredible facts and theories and commonly embellished some of the more fanciful. The result was a spreading structure of theories supported by fables, a structure top heavy with philosophical reasoning directed toward supporting prior
authorities and contemporary religious dogmas.
In the course of a thorough classical education in Germany and Italy Agricola became acquainted with the writings of Greek and Roman authors as well as the rather sterile works of the Dark and Middle Ages. Having a professional and natural interest in minerals, rocks and earths, it is particularly fortunate that he was destined to take up residence in a booming mining district. During his study of the mineral wealth opening before his eyes even the most cursory observations could not fail to demonstrate the fallacies of many of the old theories accepted as valid by his contemporaries.
Although he held the opinions of many of the older writers in high esteem he was constantly testing them on the touchstone of observation and experience and discarding those proven to be erroneous. Prior to the publication of De Natura Fossilium few writers had attempted to classify minerals. The common practice was to either list all minerals alphabetically or first describe the more common and better known minerals and then list the remaining in alphabetical order. Without the sister sciences of chemistry and crystallography the only basis for a classification in the sixteenth century was the physical properties and, with the exception of color, little attention was given to these properties.
Agricola, with the opportunity and desire to study the physical properties of minerals by observation, was able to work backward through the literature and separate many facts about minerals from the mass of fantasies of the earlier writers.
The work De Architectura by Vitruvius proved to be particularly valuable. As a result of these studies he was the first to propose a systematic mineral classification, one based upon observed physical properties. It is for this contribution in De Natura Fossilium that he is justly known as the Father of Mineralogy.
Although physical properties can be used for the sight identification of minerals, unfortunately they cannot serve as the basis for an adequate classification and his effort was doomed to failure, particularly since he was confined within the framework of the concept of the four Peripatetic elements.
This does not detract, in any manner, from Agricola’s contributions, especially when we judge them against the background of the general level of learning in his day and when we realize that it was not until the end of the eighteenth century, over two hundred years later, that the next important advances in mineralogy were to be made.
Agricola recognized and used all the physical properties of minerals known to present day mineralogists. The outline of his classification is as follows:
As would be expected he had great difficulty placing many so-called minerals in this classification, particularly the fossils and some of the materials considered as gems. Fossils were not generally recognized as such although he recognized coquina as consisting of fossil shells.
It was not possible for him to discard or discredit all the time-honored fantasies regarding minerals, particularly the mythical and magical properties ascribed to so many of them. While some are discarded others are mentioned but in context that indicates serious doubt on his part.
It is interesting to note that the one outstanding error he makes is the classification of camphor as a corpus subterraneum related to petroleum, an error based on deductive reasoning and not on observation.
De Natura Fossilium was first published by the Forben press at Basel in 1546 and later editions appeared in 1558 (folio), 1612 (12mo), and 1657 (folio). The second edition, also published by the Forben press, appeared three years after his death. The work was translated into Italian in 1612 and into German in 1809-1810.
Agricola uses some 573 Latin mineral names and 115 Greek names. Two minerals are described by concise phrases. Twenty-seven mineral or “fossil” materials are given the same Latin name as some other wholly dissimilar material and three are given Greek names. At least twenty mineral species are described for the first time and several materials or minerals are described but not named. In spite of the scope of the work there are several noteworthy omissions of mineral names undoubtedly well known to him.
Apparently Agricola was slow to accept certain changes introduced by his contemporaries, for example, the use of the name natron instead of nitrum. Aside from its historical interest this work is of particular value in giving mineral localities and describing the occurrence of many ore minerals for the first time.