Johann Friedrich Henckel

Johann Friedrich Henckel (1678 to 1744) was a Prussian physician, chemist, metallurgist and mineralogist who taught chemistry and mineralogy at the Bergakademie Freiberg. His students there included Andreas Sigismund Marggraf, Mikhail Lomonosov and Dmitri Vinogradov. Born in Merseburg, the son of a physician, he attended Merseburg Cathedral School from 1685 to 1694, studied theology and medicine at Jena from 1698, and then worked as a physician in Dresden. He took a doctorate in 1711 and moved to Freiberg. In 1728 he was elected to the Leopoldina Academy, and in 1730 he moved back to Dresden and began work on minerals. He studied the chemistry of pyrites, and because he believed that minerals form through processes such as crystallization, he rejected the theory of instantaneous creation. He died in 1744.