Xiantao stone, monkey watching the sea, immortal guiding the way, golden rooster calling heaven, etc., are named mainly according to the shape of the stone. ?
at the beginning of the earth's formation, the gravity of the earth's core sucked the dust in the universe, and the condensed dust turned into rocks, weathered into rocks, and then turned into meteorites. ?
when it does not fall into the earth's atmosphere, it is a stone, iron or a mixture of stone and iron that is free from outer space; If it falls into the atmosphere, it will become a meteorite we usually see before it is burned by the atmosphere and falls to the ground. Simply put, the so-called meteorite is the debris left by a miniature asteroid that "hit the earth".
after hundreds of millions of years, there are countless rocks in the world. Nowadays, in the field of geotechnical engineering, human beings often divide rocks into four types according to their engineering properties: extremely hard, hard, moderately hard and weak.
Extended data:
According to their genesis, rocks are mainly divided into igneous rocks (magmatic rocks), sedimentary rocks and metamorphic rocks. In the whole crust, igneous rocks account for about 95%, sedimented dao rocks account for less than 5%, and metamorphic rocks are the least. However, in different circles, the distribution ratio of the three rocks is very different.
75% of the rocks on the surface are sedimentary rocks and only 25% are igneous rocks. The deeper from the surface, the more igneous and metamorphic rocks there are. The deep crust and upper mantle are mainly composed of igneous rocks and metamorphic rocks.
igneous rocks account for 64.7% of the whole crustal volume, metamorphic rocks account for 27.4% and sedimentary rocks account for 7.9%. Basalt and gabbro account for 65.7% of all igneous rocks, while granite and other light-colored rocks account for about 34%.