Classification, Mineralogy and Industrial Potential of SiO2 Minerals and Rocks

Abstract

The various modifications of silica, especially quartz, play a central role in the composition of geological materials. Owing to their abundance and properties, SiO2 minerals and rocks have been used since the beginning of human being in different applications such as tools, weaponries, jewelleries or building materials. In modern industries, silica minerals are widely used as raw materials in high-tech applications (e.g. piezo quartz, optical devices, solar industry) or as mass products (e.g. glass sands, refractory industry, foundry industry, etc.). The occurrence of different silica minerals and the similarity in mineral composition of SiO2 rocks require a clear terminology and nomenclature of silica polymorphs and varieties as well as the different types of SiO2 rocks and their genesis. The knowledge about the development of specific properties (typomorphic properties) in dependence on the specific conditions of formation can be used both for the reconstruction of geological processes and for specific technical applications. The present work gives an overview about the state of the art of the mineralogical and petrographical nomenclature of SiO2 minerals and rocks, the analytical approach for the identification and classification of these materials, and their industrial applications.