De re metallica (Latin for On the Nature of Metals (Minerals)) is a book cataloguing the state of the art of mining, refining, and smelting metals, published a year posthumously in 1556 due to a delay in preparing woodcuts for the text. The author was Georg Bauer, whose pen name was the Latinized Georgius Agricola. The book remained the authoritative text on mining for 180 years after its publication. It was also an important chemistry text for the period and is significant in the history of chemistry.