Georgius Agricola (Georg Bauer) born in Glauchau, in the province of Saxony in what is now Germany, Agricola studied classics at Leipzig University, taught Latin and Greek for a few years, and then in 1522 began to study medicine, first at Leipzig and then at Bologna and Padua in Italy. He took his degree in 1526 and became a practicing doctor; however, he never seems to have been terribly enthusiastic about his profession, devoting most of his energy to studies of mining and geology. He began practicing medicine at Joachimsthal in 1527. Joachimsthal was an important mining center of the time, in particular for silver mining. Agricola's geological writings reflect an immense amount of study and first-hand observation, not just of rocks and minerals, but of every aspect of mining technology and practice of the time. Agricola moved in 1536 to the city of Chemnitz, also an important center of the mining industry, and was elected Burgomaster there in 1546. He not only continued his medical practice and his geological studies there, but was appointed to several public and diplomatic posts by Duke Maurice of Saxony, to whom he dedicated his book De Natura Fossilium. He died in 1555, one year before the posthumous publication of De Re Metallica, his greatest work.

De Re Metallica, literally translated, means "On the Nature of Metals," but the word metal had a wider meaning at the time, and meant any mineral. In this book, which remained the standard text on mining for two centuries, Agricola reviewed everything then known about mining, including equipment and machinery, means of finding ores - he rejected the use of divining-rods and other such magical means - methods of surveying and digging, assaying ores, smelting, mine administration, and even occupational diseases of miners. The book also contains descriptions of ores and of strata. His book was profusely illustrated; one illustration, showing mine shafts, is shown at left (click on the small image to view an enlargement). Agricola noted that rocks were laid down in definite layers, or strata, and that these layers occurred in a consistent order and could be traced over a wide area. This observation of Agricola's was one of the first contributions to stratigraphic geology, and one that would become important in understanding the arrangement and origins of the rocks of the Earth.

His work paved the way for further systematic study of the Earth and of its rocks, minerals, and fossils. He made fundamental contributions to mining geology and metallurgy, mineralogy, structural geology, and paleontology.