Marble

Classification：Metamorphic Rock

The marble is formed by limestone, dolomite and carbonate by regional metamorphism and contact metamorphism. The main component of marble is calcium carbonate.

Carbonate rocks in Marble sedimentary rocks are metamorphosed. It was named in Dali, Yunnan, China. The main minerals are recrystallized calcite and dolomite, which can be identified by the naked eye and produce bubbles by dilute hydrochloric acid. Pure Marble is white. It contains variegated colors and beautiful stripe when it contains impurities. It is the main decorative building stone and carved stone. The compressive strength of rock blocks varies with particle cementation and size, generally 49 to 117.7 MPa, and can be used as building foundation. Because it is easy to dissolve in water, there are various phenomena in Karst. It will cause reservoir leakage and collapse.

Brief introduction:
Marble is a type of metamorphic rock. It is named in Dali, Yunnan province because of its rich rock. The carbonate rocks are formed by regional metamorphism or contact metamorphism. It is mainly composed of calcite and dolomite, and contains wollastonite, talc, tremolite, diopside, Xie Changshi, quartz and calcite. A granular, granular structure (sometimes banded). Usually white and gray Marble are in the majority.

Mineral composition:
Marble is formed by regional metamorphism and contact metamorphism of limestone, dolomitic limestone and dolomite, and the content of calcite and dolomite is generally greater than 50% and some can reach 99%. But in addition to a few pure Marble, there are usually a small number of other metamorphic minerals in the general Marble. Due to the different kinds of impurities in the original rock (such as siliceous, muddy, carbonaceous, iron, volcanic detrital, etc.), as well as the temperature, pressure and water solution content of the metamorphism, the types of associated minerals in the Marble are also different. For example, in Marble formed by more pure carbonate rocks, calcite and dolomite account for more than 90%, and sometimes there are few graphite, muscovite, magnetite, pyrite and so on. Shi Ke is converted into aragonite under the condition of low temperature and high pressure. In Marble formed by siliceous carbonate rocks, it can be contained at middle and low temperature. Talcum, tremolite, Yang Qishi and quartz can contain diopside, trapezite, forsterite, wollastonite and Peridex in middle and high temperature. In high temperature and low pressure, there can be granular siliceous calcite, calcium magnesium olivine, magnesium Huang Changshi and so on. In Marble formed by muddy carbonate rocks, it can be found at middle and low temperature. It contains serpentine, chlorite, epidote, heathenite, Fu Shan stone, black mica, acid plagioclase, and micro plagioclase. In middle and high temperature, it can contain alusite, calcium aluminosilite, granolite, chrysotile, spinel, apatite, medium plagioclase, and orthopite.

Chemical composition:
It is closely related to the chemical composition of the original rocks, and is related to the characteristics of metamorphism. In the formation of metamorphic rocks, such as no metasomatism, the chemical composition of metamorphic rocks, except for H2O and CO2, basically depends on the chemical composition of Yu Yuanyan; if metasomatism, it is determined not only in the chemical composition of the original rock but also in the type and strength of the metasomatism. The chemical composition of metamorphic rocks is mainly composed of oxides such as SiO2, Al2O3, Fe2O3, FeO, MnO, CaO, MgO, K2O, Na2O, H2O, CO2, and oxygen. The chemical composition of metamorphic rocks is often larger because of the different effects of chemical active fluids on various characters in metamorphic rocks and metamorphic rocks. For example, in metamorphic rocks formed by magmatic rocks (ultrabasic acid rocks), the content of SiO2 is 35 to 78%, and in metamorphic rocks (quartz sandstone and siliceous rock), the content of SiO2 is more than 80%; while the original rock is pure limestone, it can be reduced to zero. In the metamorphism, the absolute chemical reaction is not. In the process of the metamorphic reaction, there are always some components out and out, the original rock composition always has some changes, and sometimes it is very significant. In normal metamorphic reactions, mineral dehydration and water absorption, carbonation and desarbonization often occur. These processes, in addition to temperature and pressure, are related to the properties of H2O and CO2 during the process of metamorphism. Other chemical components often show varying degrees of activity under the influence of different temperatures, pressures and external components. For example, during the process of contact metasomatism, it can be formed by double metasomatism between intrusive bodies and surrounding rocks. In the process of regional metamorphism, the stability of the chemical composition of the rock is sometimes expressed as the heat of the formation of compounds (silicate, oxide, sulfide, etc.). Generally speaking, the higher the generation heat is, the more stable the compound is. The heat generation of sulfide is low, heat generation of sulfide oxide and silicate high. Therefore, in the process of regional metamorphism, when the temperature rises, the stone elements (including the main rock forming elements K, Na, Fe, Mg, Al, Si) remain stable, while the pro copper elements show different activity according to their own characteristics. This case also partly explains why the main rock forming elements of rocks can remain unchanged or slightly changed in the process of regional metamorphism.

Structural structure:
Marble generally has a typical granular crystalline structure, the granularity is generally medium, fine particles, sometimes coarse grains, and the calcite and dolomite particles in the rock are tightly inlaid between them. In the Marble formed in some regional metamorphism, the optical axis of calcite is arranged in a directional arrangement, so that Marble has strong light transmittance, for example, some Marble can permeate 2 cm, and the transmittance of individual Marble can reach 3~4 cm. They are excellent engraving materials. The structure of Marble is mostly massive, and many Marble have different sizes of strip, stripes, plaques, spots and other structures. After processing, they become decorative building materials with different colors and pattern patterns.

Color characteristics:
Marble, in addition to pure white, has a variety of beautiful colors and patterns. The common colors are light gray, light red, light yellow, green, brown, black and so on. The main reason for the different colors and patterns is that the Marble contains a small amount of colored minerals and impurities, such as Marble containing manganese calcite in pink, Marble The graphite is gray and the serpentine is yellow green, and the chlorite, the acrostone and the diopside are green, the gold mica and the granulite are yellow, and the acamite and the calcium and aluminite are brown.

Classification:
Different types of Marble can be formed, such as pure calcite and calcite Marble and dolomite Marble after metamorphism of pure calcium and magnesium carbonate rocks. After metamorphic siliceous limestone, quartz Marble and wollastonite Marble can be formed, and graphite Marble can be formed after metamorphism of carbonaceous limestone. It can be further divided according to structural structure and color, such as white Marble, gray Marble, pink Marble, fine grain Marble, coarse Marble, strip band Marble and so on.

Use:
Marble is mainly used for engraving and building materials, and its engraving is mainly pure white, fine and uniformly distributed Marble with strong transmittance. It has strong light transmission and can enhance the gloss of Marble. They are often used to build monuments, paving floors, walls, and engraving rails. It is also used as a desktop, stone screen, or other decoration, which can be used in a uniform Marble with a pure white structure according to different needs, or Marble with a variety of colors and patterns. Marble is also used as an insulating plate in electrical materials. Such Marble requires good insulation and can't contain impurities, especially conductive impurities such as pyrite and magnetite. Marble with high calcium content can also be used as raw material for lime and cement. China is one of the earliest and most important countries to use Marble. The buffalo was carved with Marble in the Yin Dynasty of the twelfth Century B.C., and Marble was widely used in many famous ancient and modern architectures all over the country. The Chinese watch in front of the Tiananmen, the white marble railings in the the Imperial Palace and the 250 tons of Yunlong stone, the relief of the monument to the people's heroes, the big stone columns and banquet hall in front of the Great Hall of the people, the station of the subway in Beijing, are all decorated with Marble.