Si Tong, malm
Sandstone is a sedimentary rock, which is mainly composed of minerals and rock particles (particle size is 0.06-2mm), and contains more than 60% of silica. It has a porous structure formed by the condensation of silicon dioxide, iron oxide, carbonate or clay. Classification: Mainly divided into blue-gray sandstone, brown sandstone, seasonal sandstone, quartzite, gravel and siltstone.
slabstone
Slate is a metamorphic rock with plate-like structure and little recrystallization. The original rock is argillaceous, silty or neutral tuff, which can be stripped into thin slices along the foliation direction. The color of slate varies with the impurities it contains, and the iron-containing ones are red or yellow. Carbon is black or gray; Calcium bubbles when it meets hydrochloric acid, so it is generally named and classified by color, such as green slate, black slate and calcareous slate.
marble
Marble consists of sedimentary rocks and metamorphic rocks of sedimentary rocks, which are metamorphic rocks formed by recrystallization of limestone, usually accompanied by the texture of biological relics. From a commercial point of view, all naturally occurring calcareous rocks that can be polished are called marble, as are some dolomite and serpentine.
granite
Granite belongs to igneous rock, which is formed by underground magma ejection and intrusion cooling crystallization, as well as granitic metamorphic rocks. With visible crystal structure and texture. The specific gravity of granite is 2.63 ~2.75, and the compressive strength is1.050 ~1.4kg/cm2 (1.5000 ~ 20000 lb/in2). Because granite is stronger than sandstone, limestone and marble, it is more difficult to mine.
limestone
Limestone is a kind of rock formed by sedimentary sources, and its main components are calcium carbonate, calcium magnesium carbonate or a mixture of calcium carbonate and magnesium carbonate. Recrystallized limestone, solid microcrystalline limestone and polished travertine are all promoted and sold as limestone or marble, especially in the United States.