gems, mineralogy, Dana, reference

This third volume of the seventh edition of Dana’s System of Mineralogy is devoted to the silica minerals and provides a comprehensive systematic treatment of the mineralogy of SiO₂ and its polymorphs and varieties. It describes the crystallography, physical and optical properties, chemistry, occurrence, associations, alteration, synthesis, and geographical distribution of quartz, tridymite, cristobalite, coesite, opal, and related silica materials, incorporating the extensive mineralogical literature accumulated since earlier editions of Dana. Particular attention is given to the many crystalline and cryptocrystalline varieties of quartz, including rock crystal, amethyst, smoky quartz, citrine, chalcedony, agate, jasper, and other gem and ornamental materials. Detailed locality information, analytical data, structural relationships, nomenclature, and references make the volume an important reference for both mineralogists and gemologists and a major synthesis of contemporary knowledge of the silica mineral group.