Characteristic of the Spessart region, which lies between Aschaffenburg, Gelnhausen, Schlüchtern, Lohr, Wertheim, and Miltenberg, are three groups of rocks: the crystalline basement, the Permo-Mesozoic cover rocks, and the younger deposits of the Tertiary-Quaternary that lie above them. The area is well-known among collectors for its variety of minerals, such as spessartine. In the general section, the authors provide a comprehensive overview of the classification, rocks, structure, and geological development of the Spessart, drawing on the latest research. The extremely complex geology of the Vorspessart crystalline (metamorphic age approximately 330 million years) is covered in detail, as is the sedimentary cover (Rotliegend-Quaternary), which constitutes the majority of the Spessart's area. There are also references to deposits, mines, quarries, mineral sites, and cultural aspects.