There are different types of Quartzite rocks found on the Earth’s crust. These rocks differ in many important properties and many types of quartzite rocks are also used for commercial purposes. ‘TypesOf.com’ is endeavoring to highlight what quartzite rocks are and the different types of quartzite rocks.
There are uncountable varieties of rocks present of the Earth and no two rock samples are alike. The pressure and temperature conditions in which they form, their depth of formation, the mode of crystallization and even the concentration of minerals crystallizing to form that rock lead to significant amount of differences in each and every rock sample. For the convenience of petrologists, rocks are broadly classified according to the mode of formation, the conditions during crystallization and the minerals crystallizing.
Quartzite is a tough and hard metamorphic rock made up almost entirely of quartz (silica) and contains fragmentary amounts of feldspar and mica. It is generally white to grey in color, has a fine grained texture. The colors of different types of quartzite rocks can range from pink to yellow as well depending on the various amounts of iron oxide impurities present in the rock. It is resistant to physical and chemical weathering, that is, it is considerably stable and does not react with common weathering agents such as natural acids or water. Because it is so hard, it is also resilient against wind and water action.
Quartzite is a metamorphic rock. This implies that quartzite is formed due to the recrystallization of sandstone under tremendous amounts of pressure and temperature at great depths inside the Earth. As a sandstone rock continued to be buried, temperature and pressure conditions around it changed, leading to recrystallization of the sandstone thereby making it more stable for the new environment, hence producing a new type of rock, quartzite.
There are two types of quartzite rocks when classifying according to the mode of formation. Metaquartzite rocks are formed when sandstone is recrystallized due to deep burial in the Earth and subsequent increase in pressure and temperature conditions. In these types of quartzite rocks almost all traces of sedimentary structures such as bedding and original grains are erased.
Orthoquartzite rocks are formed at relatively lower burial depth and subsequent low temperatures and pressures. Here, the fluids circulating around the sandstone rock fill up the spaces between the grains thus producing silica cement. In these types of quartzite rocks, the original grains and sedimentary structure of the sandstone are still evident.
Quartzite rocks have innumerous use in the commercial and building sector. Due to its resilience to weathering and erosion, quartzite rocks make excellent construction material. There hardness gives them a use in the diamond cutting industry where it is used in a saw blade meant to cut diamond. Orthoquartzite rocks hold some of the most excellent fossil records of the geological history of the earth.
Certain types of quartzite rocks, which differ by virtue of color, that is, alteration due to presence of iron oxide, zircon, rutile, magnetite, such as the pink quartzite are used in the commercial and gems industry. Pink quartzite or the rose quartz, and purple quartzite or the amethysts are some of the very popular gem minerals present in the crust.