Portrait of the German mineralogist Agricola, whose name was Georg Bauer (1494-1555). He lived as a physician in some of the small mining towns of Saxony. His book, On the Subject of Metals, was clearly written & heavily illustrated, and summarized all the practical knowledge acquired by the Saxon miners of the day. It is regarded as the first text on mineralogy & Agricola as the father of mineralogy. He also wrote a book called The Nature of Fossils which classified minerals in perhaps the first comprehensive system.