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The river pebble is a kind of pure natural stone. It is taken from the sandstone mountain produced by the uplift of the ancient riverbed after the crustal movement that occurred thousands of years ago. It has experienced continuous crushing and friction during the flooding and running of water. The main chemical component is silica, followed by a small amount of iron oxide and trace elements such as manganese, copper, aluminum and magnesium. During the evolution of vicissitudes of tens of thousands of years, they have suffered from the wave-washing movement, and they have lost irregular edges and corners by gravel collision friction. The surface is smooth and clean, the average content of SiO2 is 85%, and the highest compressive strength can reach 300MPa or more. It is more than 7 degrees Mohs, and has good pressure resistance, wear resistance and corrosion resistance. It is an ideal widely used mechanism sand material.
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