Quartzite is a very special rock. It arises when sandstones reach great depths of several kilometers through lengthy geological processes. There, at high temperatures but relatively low pressures, a transformation takes place, which is known as metamorphosis. The individual grains of sand of the sandstones interlock firmly with each other and form a typical mosaic structure. This can be observed under the microscope. Quartz is the most important mineral involved in the structure of quartzite - and almost the only one. Other minerals such as mica, iron oxides and so-called heavy minerals are usually only contained in small percentages. In Rhineland-Palatinate, quartzites are preferred in the mountain ranges of Hunsrück, Eifel, Taunus and Westerwald, where they form the core of the mountain ridges because of their hardness and weather resistance. There they emerged during the formation of the Rhenish Slate Mountains over 300 million years ago. In the district of Birkenfeld, quartzites and quartzitic sandstones are extracted in the Allenbach and Kappelbach quarries of the Juchem Niederwörresbach group. They are either processed into chippings or gravel, which are mainly used in the construction industry. Due to its light gray color and resistance to abrasion, quartzite high-grade chippings are also used as a so-called brightener in road paving. Quartzite is used as a stone in landscaping and horticulture, as a brick and for floor coverings.