Werner was an eloquent, systematic teacher with great charm of manner. He kept in mind the practical purposes of mining, and soon people flocked to Freiberg to hear him from all the quarters of Europe. He had before long disciples in every land. He saw all phenomena from the standpoint of the geologist. He knew the medicinal, as well as the economic, value of minerals. He knew the relation of the soil to the rocks, and the effects of both on racial characteristics. Building-stone determines style of architecture. Mountains and river-courses have bearing on military tactics. He turned his linguistic knowledge to account and furnished geology with a definite nomenclature. Alex. v. Humboldt, Robert Jameson, D'Aubuisson, Weiss (the teacher of Froebel), were among his students. Crystallography and mineralogy became the fashion. Goethe was among the enthusiasts, and philosophers like Schelling, under the spell of the new science, almost deified the physical universe.
Werner considered all rocks as having originated by crystallization, either chemical or mechanical, from an aqueous solution--a universal primitive ocean. He was a Neptunist, as opposed to the Vulcanists or Plutonists, who believed in the existence of a central fiery mass. Werner thought that the earth showed universal strata like the layers of an onion, the mountains being formed by erosion, subsidence, cavings-in. In his judgment granite was a primitive rock formed previous to animal and vegetable life (hence without organic remains) by chemical precipitation. Silicious slate was formed later by mechanical crystallization. At this period organized fossils first appear. Sedimentary rocks, like old red sandstone, and, according to Werner, basalt, are in a third class. Drift, sand, rubble, boulders, come next; and finally volcanic products, like lava, ashes, pumice. He was quite positive that all basalt was of aqueous origin and of quite recent formation. This part of his teaching was soon challenged. He was truer to his own essential purposes in writing a valuable treatise on metalliferous veins (_Die Neue Theorie der Erzgänge_), but even there his general views are apparent, for he holds that veins are clefts filled in from above by crystallization from aqueous solution.
