Rock is composed of one or several minerals and natural glass, with a stable appearance of solid aggregates. Rocks composed of a mineral are called monoliths, such as marble composed of calcite, quartzite composed of quartz; there are several minerals composed of rock called complex rock, such as granite from quartz, feldspar and mica and other minerals , Gabbro composed of basic plagioclase and pyroxene, and so on. There is no certain shape of the liquid such as oil, gas such as natural gas and loose sand, mud, etc., are not rock.Rock is one of the substances that make up the crust and constitute the main component of the earth's lithosphere. Among them, feldspar is the most important crust in the crust composition, the proportion of 60% , quartz is the second largest number of ore.The rocks are classified according to their genesis, tectonics and chemical composition. Most rocks contain silica (SiO2), while 74.3% of the crust is the latter. The silicon content in the rock is one of the important factors in determining the rock properties.Rock is an important source of early human tools and is of great importance in human evolution. Thus, the first civilized period of mankind was called the Stone Age. Rock has always been an important material and tool for human life and production.
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