Bauer (1844-1917) was a German mineralogist. He was educated at the University of Tübingen, with post graduate work in mineralogy at Univerisity of Berlin. Bauer earned a professorship of mineralogy and geology at Königsberg, Germany in 1875, before being named professor of mineralogy and petrology at the University of Marburg in 1884. He edited Beitrage zur Mineralogie and Neues Jahrbuch für Mineralogie, Geologie und Paläontologie from 1880 to 1891. He was asked to write a comprehensive work on gemstones similar to Kunz’s Gems and Precious Stones of North America. This led to the publication of Edelsteinkunde and the later English translation “Precious Stones. This work is one of the greatest gemological works ever published with respects to the treatment of world gem localities and the scientific study of gemology. The text first treats gemstone properties, occurrences, application of gemstones to ornament and technology. The work then provides descriptions with data on properties, occurrences, uses, value and trade. Next a more in depth treatment of gemstone identification is provided. The English translation incorporates new information (localities, recently discovered diamond deposits, and new gem data.