Tell me about Quartzite Stone
What is quartzite?
What is quartzite made of?
How is quartzite formed?
From medium to fine-grained metamorphic rock with a quartz content of at least 98% is called quartzite. The rock is extremely insensitive to any kind of environmental influences. In most cases, natural quartzite has a white to off-white color; if it is yellowish or even reddish, it means that iron minerals have been added. In addition to the natural color, the most common is yellow rock, which is caused by limonite. Impurities with pyrite and magnetite often form a grayish to brownish natural stone. If the quartzite is rather bluish, the minerals kyanite and dumortierite are responsible.
Origin and occurrence of Quartize Stone?
Sinter the recrystallized, interconnected quartz grains using a pressure solution at the grain boundaries (sinter = rock created by mineral deposition). Depending on the degree of metamorphosis, this sometimes results in brittle, hard chunks of rock. These are extremely insensitive to the weather. In the case of weakly metamorphic quartzite, frost or abrasion resistance is no longer or is only minimally guaranteed. The metamorphosis from sandstone, chert, pebble or radiolarite is the starting form of quartzite. Temperature, pressure and mechanical stress deform the individual quartz grains using a pressure solution. The crystal lattice is newly formed and recrystallization grows beyond the original grain boundaries. The networked, dense structure creates a layered shape that can be split. Depending on the metamorphosis, the existing pore spaces have disappeared, clay components are converted into mica minerals (silver = muscovite, green = phengite and organic components into graphite, and inorganic substances are broken down. These substances are no longer present in real quartzites. According to research documents, quartization begins at over 200 ° C at a depth of at least 600 meters. In addition to the color, the cleavage is one of the most important distinguishing features of quartzite. Swedish block quartzite and Brazilian blue Azul do Macaubas are difficult to split. Quartzite from the Alps, Bulgaria (Balkan Mountains), Spain (Córdoba, Segovia) or in Scandinavia is easier to split because it is provided with mica layers that indicate the direction of splitting. There is also optimal rock in the Kaniapiskau supergroup of the Labrador Basin on the northeastern edge of the Superior Kraton in North America or in the Jebel-Uweinat in the East Sahara Kraton in Egypt, as well as in the São Francisco Kraton in Brazil.
Wrong description and use of Quartzites!
Quartzite is widespread worldwide thanks to metamorphosis, but other types of rock are often referred to as quartzite. For example, the sandstone solidified thanks to silica, which can be found in Germany in the Hunsrück, Taunus, Rhenish Slate Mountains or in the Eifel as well as in the Westerwald. This quartzite sandstone has also been found in the western Harz, where it is usually somewhat reddish. This rock was already used as a flint substitute in the Stone Age since it is extremely hard. Real quartzite or silicified sandstone was previously used to make tools. In Egypt’s history of architecture or art history, coffins and other works of art were carved out of quartzite, and the Colossi of Memnon in the Temple of Amenophis III, as well as the coffins of Tutenchamun and Hatshepsut, still bear witness to this today.
Nowadays quartzites are used in industrial manufacturing in the construction sector. For indoor use as flooring or worktops and outdoors as weather-resistant flooring.
However, e.g. B. in Brazilian pink quartzite, due to the pore size, liquid dirt particles nest, in blue Azul, do Macaubas, also from Brazil, gray spots form due to the mineral sericite in combination with CO2 and water. Outside, the porosity is also important, because certain types are resistant to moss or can be blown up by de-icing salt or frost. The color of the quartzite is decisive for the resistance to chemicals. Yellowish quartzites are sensitive to phosphoric or hydrochloric acid, potash or sodium hydroxide, on the other hand, damages almost all quartzites and the colored minerals in the rock. When laying as a floor covering, the temperature expansion with regard to underfloor heating or outdoors must be taken into account in any case and a substructure selected accordingly.