GeoRef This database is a comprehensive geoscience resource containing over 4 million bibliographic records covering subjects such as mineralogy and crystallography, general mineralogy, mineralogy of silicates, and mineralogy of non-silicates. Sources covered include journal articles, books, maps, conference papers, reports, and theses. Geology of North America is covered from 1666 to the present, and geology of the world is covered from 1933 to the present. This database is produced by the American Geosciences Institute.