Is there a specification for the name of marble?

General description: Marble, also known as marble, is recrystallized limestone, as long as the composition is CaCO3. Limestone softens at high temperature and high pressure, and when the minerals in it change, it recrystallizes to form marble. The main components are calcium and dolomite, with many colors, usually obvious patterns and many mineral particles. Mohs hardness is between 2.5 and 5. Marble is a metamorphic rock formed by high temperature and high pressure in the earth's crust. The internal force of the crust promotes the qualitative change of the original rock, that is, the structure, structure and mineral composition of the original rock change. The new rocks formed by qualitative change are called metamorphic rocks. Marble is mainly composed of calcite, limestone, serpentine and dolomite. Its main component is calcium carbonate, accounting for more than 50%. Because marble generally contains impurities, calcium carbonate is easily weathered and dissolved by carbon dioxide, carbide and water vapor in the atmosphere, and the surface quickly loses its luster. Marble is generally soft, which is relative to granite. In interior decoration, marble is suitable for TV cabinets, window sills and indoor floors. Marble is a commodity name, not a petrological definition. Marble is a kind of natural building decorative stone, which generally refers to metamorphic or non-metamorphic carbonate rock with decorative function, and can be processed into building stone or handicraft. It is named after the colorful and ornate stones produced in Diancang Mountain, Dali City, Yunnan Province, China. Marble generally refers to marble, limestone, dolomite, skarn and marble formed by different alteration of carbonate rocks. Marble is mainly used for processing into various shapes and plates, making walls, floors, platforms and columns of buildings, and is a precious material for furniture inlay. It is also often used as a material for memorial buildings such as monuments, towers and statues. Marble can also be carved into handicrafts, stationery, lamps, utensils and other practical works of art. Marble is soft, beautiful, solemn, elegant in style and diverse in color. It is an ideal material for decorating luxury buildings and a traditional material for artistic carving.

Marble classification

Marble is divided into three categories:

Dolomite: the content of magnesite (magnesium calcium carbonate) is more than 40%.

Forsterite: The content of magnesite (magnesium calcium carbonate) is between 5% and 40%.

Calcite: the content of magnesite (magnesium calcium carbonate) is less than 5%.

Characteristics of ore raw materials

(1) process classification

Marble is a kind of rock represented by marble, including carbonate rocks and related metamorphic rocks, which is generally softer than granite. Common rocks are marble, limestone, dolomite and skarn. Marble varieties have different naming principles, some are named after the origin and color, such as Dandong Green and Tieling Red. Some are named after patterns and colors, such as Snow White and Ai Yeqing. Some are named after patterns, such as autumn scenery and The Waves. Some are traditional names, such as white marble and crystal jet. Therefore, due to different producing areas, the phenomenon of the same kind of synonyms or different rocks with the same name often occurs.

Marble produced in China can be roughly divided into seven series according to the basic color of polished surface: white, yellow, green, gray, red, brown and black. Each series can be divided into several categories according to the color and pattern characteristics of its polished surface, such as: white marble, rosin yellow, Dandong green, Hangzhou gray and so on. The pattern and crystal size of marble are ever-changing, including landscape type, moire type and pattern type (line pattern, willow pattern, portrait, paleontology and so on. ) and snowflake type. Modern architecture is colorful and constantly changing. Therefore, decorative marble also requires many varieties and colors, which can be used in different parts of the building. Generally, monochromatic marble requires uniform color; Colored marble requires a gradual transition in pattern and depth; Patterned marble requires clear patterns, bright colors and strong regularity. In short, it is best to have beautiful colors, which are convenient for large-scale splicing and decoration, and can be supplied in batches with consistent colors. See table 4.25. 1 for the technical classification of marble in China.

(2) Mineral composition and main characteristics

The mineral composition and characteristics of marble are directly related to the performance and decorative effect of its products.

(iii) Chemical composition and physical characteristics

The chemical composition of marble generally does not play a major role in whether it can be used, but it can directly explain the lithology and indirectly affect the physical and chemical properties, which is of certain significance for evaluating the machinability, weather resistance and corrosion resistance of marble.

The physical properties of marble are an important index to judge its machinability, and also an important reference for its performance and application scope.

The use of marble

Marble has beautiful colors and patterns, high compressive strength, good physical and chemical properties, wide distribution of resources and easy processing. With the development of economy, the application scope of marble is expanding and the consumption is increasing, which plays an important role in people's lives. Especially in recent 10 years, with the large-scale exploitation, industrial processing and international trade of marble, a large number of marble decorative boards have entered the architectural decoration industry, not only for luxury public buildings, but also for home decoration. Marble is also widely used to make exquisite utensils, such as furniture, lamps, smoking sets and artistic sculptures. Some marble (including limestone, dolomite, marble, etc. ) can also be used as alkali-resistant materials. Gravel and scraps produced in the process of marble mining and processing are also often used to produce artificial stone, terrazzo, stone rice and stone powder, and can be used as fillers in coatings, plastics, rubber and other industries.

Industrial technical requirements

Due to the different applications of natural marble, its industrial technical requirements also have different emphases.

1. Main requirements of natural marble blocks

The main requirements of building materials industry standard (JC202-92) for natural marble blocks are as follows:

The block must have the shape of a right-angled parallelepiped.

The specifications and dimensions of raw materials require a length greater than or equal to 100cm, a width greater than or equal to 50cm and a height greater than or equal to 70cm.

The appearance quality requirements of the same batch of raw materials should be basically the same in hue and pattern; Appearance quality grades such as missing corners, missing edges and cracks. Raw materials shall comply with the provisions in Table 4.25.6.

Physical performance requirements: the bulk density is not less than 2.6g/cm3；; ; The water absorption rate is not more than 0.75%; Dry compressive strength is not less than 20MPa；; The bending strength is not less than 7.0 MPa.

2. Quality requirements of marble for craft carving

It is required that the marble structure is compact, the particles are uniform and not easy to fall off, there are no cracks and inclusions, and the color, pattern, fragmentation and shape meet the molding requirements. The general requirement is greater than 0. 15m3. If it is used outdoors, fresh rock surface is not needed, but it requires good weather resistance and low water absorption.

3. Quality requirements of electrical insulation board

Many nonferrous metals, rare metals, precious metals and nonmetallic minerals are all related to marble in origin. It is also an excellent building material and handicraft raw material. Marble has low hardness, which belongs to medium hardness stone and is easy to mine and process. The polished plate presents decorative patterns or color textures, which are very beautiful and can be used as indoor and outdoor decorative materials. Wastes from mining and processing can be made into handicrafts or crushed into terrazzo, terrazzo and other high-quality aggregates, and a few high-density and homogeneous ones can be used for artistic carving and decoration. Because marble is basically composed of pure calcium carbonate or magnesium carbonate, it is extremely sensitive to the dissolution of acid-polluted air. In the urban atmosphere, carbonic acid separated from carbon dioxide and sulfuric acid generated from smoke and dust are always in contact with marble, which affects the supply of marble to varying degrees. In any case, marble is still an ideal material for architectural decoration and sculpture.

Resource situation

China is extremely rich in marble mineral resources, with large reserves and many varieties, and its total reserves rank among the top in the world. According to incomplete statistics, it is found that there are nearly 400 varieties of marble in China, among which the varieties with different colors are more precious as follows.

● Pure white: Beijing Fangshan white marble; Anhui Huaining, Guichi white marble; Hebei Quyang and Laiyuan white marble; Sichuan Baoxing Shu Baiyu; Jiangsu Ganyu white marble; White marble in Cangshan, Dali, Yunnan; Shandong Pingdu and Ye County Snow White, etc.

● Pure black: Guilin black in Guilin, Guangxi; Black marble in Shaoyang, Hunan; Mo Yu and King Venus in Cangshan, Shandong; Henan Anyang Moyuhei, etc.

● The red ones are: Anhui Lingbi Hongluo; Nanjiang Red in Nanjiang, Sichuan; Laishui red in Laishui, Hebei, and Fuping red in Fuping; Northeast red in Tieling, Liaoning;

● Gray ones are: Hangzhou emblem in Zhejiang; Cloud ash in Dali, Yunnan;

● Yellow ones are: Henan Zhechuan rosin yellow, rosin jade, beige.

● The green ones are: Dandong Green in Dandong, Liaoning; Laiyang green in Laiyang, Shandong, and surf jade in Qixia; Anhui Huaining Bibo, etc.

● Colored flowers include: spring flowers, autumn flowers and ink flowers in Yunnan; Plum blossoms on a snowy night in Quzhou, Zhejiang.

evaluation methodology

Grade selection: according to the allowable deviation of specifications, flatness and angular tolerance, appearance quality, surface smoothness and other indicators, marble plates are divided into three grades: excellent, first-class and qualified; The grading identification of marble plates is mainly identified by the detection of instruments and measuring tools.

Check the appearance quality: the appearance of different grades of marble plates is different. Because marble is naturally formed, defects are inevitable. At the same time, the advantages and disadvantages of processing equipment and measuring tools are also the reasons for plate defects. Some plates are not full (warped or sunken) and have defects (cracks, sand holes, spots, etc.). ), and the specifications are different (such as lack of edges and corners, wrong plates). According to national standards, all grades of marble plates are allowed to have certain defects, but the superior products are not so obvious.

Choose patterns and colors: Marble plates are rich in colors, diverse in colors and different in patterns, which is the precious charm of marble plates. The basic consistency of color tone, small color difference and beautiful pattern are the concrete manifestations of excellent varieties, otherwise the decorative effect will be seriously affected.

Detection of surface gloss: The surface gloss of marble board will greatly affect the decorative effect. Generally speaking, the polished surface of high-quality marble plate should have a mirror-like luster, which can clearly reflect the scenery. However, due to the different chemical composition of different quality marble, even the products of the same grade will have great differences in gloss. Of course, there will be some differences in the surface gloss of different grades of the same material. In addition, the strength and water absorption of marble slab are also important indexes to evaluate the quality of marble.

Characteristics and advantages of marble;

1. No deformation, high hardness and strong wear resistance.

2. Wear resistance, high temperature resistance and maintenance-free.

3. Physically stable, fine structure, impact crystal grains falling off, no burr on the surface, stable material, no deformation for a long time, small linear expansion coefficient, high mechanical precision, rust prevention, antimagnetic and insulation.

First, after long-term natural aging, the rock has a uniform structure, a very small linear expansion coefficient, complete disappearance of internal stress and no deformation.

Second, it has good rigidity, high hardness, strong wear resistance and small temperature deformation.

Third, it is not afraid of acid and alkali corrosion, rust, oil pollution and dust, and its maintenance is convenient and simple, and its service life is long.

4. There will be no scratches, and it will not stop at constant temperature, and its original physical properties can be maintained at normal temperature.

Five, no magnetization, measurement can move smoothly, no hysteresis, not affected by moisture, plane weighing. Physical properties: specific gravity 2970-3070kg/m3, compressive strength 2500-2600kg/cm3, elastic coefficient1.3-1.5×106kg/cm2, water absorption.

Maintenance of marble

Marble is easy to dye, so use less water when cleaning. Wipe regularly with a damp cloth containing mild detergent, then dry it and polish it with a clean soft cloth. It is difficult to treat badly worn marble furniture. It can be wiped with steel wool and then polished with an electric grinder to restore luster. Or wipe it carefully with a liquid scrubbing agent, and clean the stain with lemon juice or vinegar, but it is best for the lemon to stay on it for no more than 2 minutes. Repeat the operation if necessary, then clean and dry. For minor abrasions, special marble cleaners and care agents can be used. Old or expensive marble furniture should be handled by professionals.