Agricola, Georgius. De Natura Fossilium. ,
De Natura Fossilium (1546) is considered one of the most important mineralogical/gemological works of all time. Unlike his predecessors, he provided comments of considerable accuracy on the nature, properties, and treatment of gemstones. The descriptions indicate a first hand knowledge of many of the gems listed. It is evident that he relied on the writings of Pliny to describe stones of which he had no personal knowledge.