All that glitters: fool's gold in the early-modern era.

Natural philosophers of the early-modern period perceived fool's gold or iron pyrites as a substance required for the formation of metals, and chemists such as Johann Glauber speculated the vitriol produced from pyrites was the source of the legendary philosopher's stone. The sulphurous exhalations of fool's gold were also thought by members of the early Royal Society to be the basis of a variety of meteorological, geological and medical effects, including the production of thunder, lightning, earthquakes and volcanoes, fossilisation and petrifaction, as well as the principal cause of bladder and gallstones.