Marble, granite and slate are the commodity categories of decorative stone, and there are hundreds of commodity varieties, which are mainly used for processing into various decorative boards. The main uses of stone are shown in table 3-25- 1.

Table 3-25- 1 Main uses of stone materials

China is rich in decorative stone resources, with large reserves and rich varieties, ranking among the best in the world. The rocks that can be used as decorative stones are sedimentary rocks, magmatic rocks and metamorphic rocks, which are produced in various geological ages and distributed all over the country. There are more than 400 kinds of marble, among which white marble, pale jade, snowflake white, Guilin black, jet, red snail, Nanjiang red, rosin yellow, Dandong green and Laiyang green are all excellent works. There are more than 65,438+000 varieties of granite, among which Lushan Red, Jinan black, Xuelv, Panshihei, Miyilv and Shuifurong sell well abroad and are well received by users.

Second, the classification of marble and granite in China

1. Classification of marble

According to the basic color of the polished surface of marble, it can be roughly divided into seven series: white, yellow, green, gray, red, brown and black, and each series can be divided into several subcategories according to the color and pattern characteristics of the polished surface, as shown in Table 3-25-2.

Table 3-25-2 Classification Table of Marble Technology in China

2. Classification of granite

According to the basic tone of granite polished surface, it can be divided into four series: light color, red color, black color and rare color. According to their structure, each series is divided into different varieties, such as fine-grained, medium-grained, coarse-grained, large-flowered (large-spotted), as shown in Table 3-25-3.

Table 3-25-3 Technical Classification of Granites in China

Chemical Composition and Physical Properties of Marble and Granite

1. Chemical composition of common marble and granite

Generally speaking, the chemical composition of stone does not play a major role in its utilization, but it can directly show its lithology and indirectly affect the physical and chemical properties of stone. It has certain significance for the evaluation of processability, weatherability and corrosion resistance. See Table 3-25-4 for mineral composition and Table 3-25-5 for chemical composition of common marble and granite.

Table 3-25-4 Mineral Composition and Main Features of Some Common Stones

Table 3-25-5 Chemical Composition of Common Stone Materials

2. Physical properties of ordinary marble and granite

The physical properties of stone are an important index to judge the machinability of stone, and also an important reference for its performance and application scope. See Table 3-25-6 for the physical properties of ordinary marble and granite.

Table 3-25-6 Physical Properties of Common Stone Materials

3. Properties of red, green and black granites in China.

There are many varieties of red granite in China. Among the "China Famous Stones" in 1998, there are 34 kinds of red granite, accounting for 4 1% of all 83 famous stones. Table 3-25-7 and Table 3-25-8 respectively list the characteristics of red granite varieties and fine varieties in China.

Table 3-25-7 Statistics of Red Granite Varieties in China

Table 3-25-8 List of Main High Quality Red Granite Varieties in China

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Note: ① those with "★" were rated as "China famous stone varieties" in 1998; (2) The radioactivity index of six yuan red is the natural radioactivity specific activity of the finished product.

Although only three varieties of green granite in 1998 were rated as famous stones in China, there are many excellent varieties of green granite in China. Table 3-25-9, Table 3-25- 10 and Table 3-25- 1 1 respectively list the varieties, genetic classification and performance of excellent green granite varieties.

Table 3-25-9 Statistics of Green Granite Varieties in China Provinces (Cities, Districts)

Table 3-25- 10 Genetic classification and its representative varieties

Table 3-25- 1 1 List of Main Excellent Varieties of Green Granite in China

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Note: those with "★" and 1998 were rated as "China famous stone varieties".

The black granite produced in China enjoys a high reputation in the international market. Table 3-25- 12 lists the varieties of black granite in China. The following briefly introduces several main black granites.

Table 3-25- 12 China black granite variety statistics

Note: Those marked with ★ are "China Famous Stone Varieties".

Fengzhenhei, Taibaiqing and Fuping Heifengzhenhei (international number G 15 10) mining areas are located in Jiulongwan Township and Sanyiquan Township, fengzhen city City, Inner Mongolia; Taibaiqing mining area is located in Ciyao Township, Hunyuan; Fuping Black Mine is located in Mutiantian Township, Fuping County, Hebei Province. The rock types of these three black granites are mainly gabbro, gabbro porphyrite, gabbro porphyrite and diabase. See table 3-25- 13 for physical and chemical properties.

Table 3-25- 13 Physical and chemical properties of stone materials such as Fengzhenhei

Fuding black international code G35 18, pure black, uniform structure, stable color, no pores, almonds, colorless lines and spots, high compressive and flexural strength and good gloss. The rock is olivine basalt. Produced in Zhangdai, Berlin Town, fuding city, Fujian.

Jinan black international code G370 1, grayish black or black with white spots, compressive strength of 237. 13MPa, flexural strength of 36.67MPa, Shore hardness of 80HS and glossiness of 95 degrees. Produced in Huashan area of Jinan City, the rock belongs to Yanshanian gabbro.

Emerald black and Lushan black emerald green are green-dark green, with compressive strength of 2 17MPa, flexural strength of 36MPa and glossiness of 80 degrees. Produced in Wuning County, Jiangxi Province, the rock is diabase. Lushan black is black, with compressive strength of 223MPa, flexural strength of 18.7MPa, glossiness of > 80 degrees and Shore hardness of > > 79HS. Produced in Jiujiang, Lushan City, the rock is diabase.

Shengzhou Moyu international number G33 14, dark gray-black, gloss > 100 degrees. Produced in Guimen Township, Shengzhou City, Zhejiang Province, the rock is olivine gabbro.

Kangmeihei international code G35 1 1, dark black and dark green, is called "China Stone" in Japan. Produced in Quanzhou, Fujian, the rock is gabbro.

4. Radioactivity index of granite

In order to prevent the radioactive harm of stone products to human body and environment, the following two standards should be followed. 1. The Graded Control Standard for Radiological Protection of Natural Stone Products (JC5 18-93) stipulates that the radium equivalent concentration of Class A products is ≤ 350 bq kg- 1, and the specific activity CRA is ≤ 200 bqkg-1,so its application scope is not limited; Class b products ≤ 700 bq kg- 1, CRA ≤ 250 bq kg- 1, which cannot be used for interior decoration, but can be used for interior and exterior decoration of all other buildings; Class C products ≤ 1000 bq kg- 1 can be used for external decoration of all buildings. 2. The Radiological Hygienic Standard for Building Materials (GB6566-86) stipulates that the specific activities (Bq/kg) of radium -226(ARa), thorium -232(ATh) and potassium -40(AK) in finished building materials used for building houses and public buildings shall meet the following requirements: ARA/232. The latter standard is basically consistent with the provisions of Class A products in the previous standard.

Whether the specific activity of stone should be tested should be judged according to its gamma irradiation rate: when the gamma irradiation rate is ≤ 5.2×10-3 μ c/kg h, it is not necessary to test; On the other hand, the specific activities of radium -226, thorium -232 and potassium -40 must be analyzed and determined. After deducting the allowable cosmic radiation background, 5.2×10-3 μ c/kg h is equivalent to the 40γ irradiation rate specified in "Radioactivity Evaluation of Rocks and Mines". Therefore, 40γ has reference value for stone mines.

Among the varieties of granite, the red variety has a higher radioactivity index, and the redder and brighter the granite, the higher the radioactivity intensity. Nevertheless, the radioactive intensity of most red granites is within the specified index. Among the varieties of granite with radioactivity exceeding the standard, green granite, such as rhododendron green, has a wide range of exceeding the standard. See table 3-25- 14 for the radioactivity index of some green granites.

Table 3-25- 14 Radioactivity Index of Some Green Granites

Fourth, product standards and quality requirements

1. Product standards and quality requirements of natural marble

JC79-84, a standard issued by the Ministry of Natural Marble, is suitable for the board made of natural marble by sawing, grinding and cutting, and is mainly used for indoor and outdoor decoration of building engineering. See table 3-25- 15 for the allowable tolerance of flat plate specifications, table 3-25- 16 for the allowable deviation of flatness, table 3-25- 17 for the allowable deviation of angle, and table 3-25- 18 for the gloss index.

Table 3-25- 15 Allowable deviation of natural marble plate specifications

Table 3-25- 16 Allowable deviation of flatness of natural marble slab

Table 3-25- 17 allowable deviation of natural marble slab angle

Table 3-25- 18 Glossy Index of Natural Marble Board

Note: When the quality of the listed stones changes significantly, the glossiness index shall be determined by the designer, user and manufacturer together with the standard samples of the selected varieties, and the glossiness measured by the inspection method in this standard shall be taken as the index.

Table 3-25- 19 natural marble slab edge defect range

See table 3-25- 19 for the appearance technical requirements of natural marble slabs.

2. Standard for Natural Granite Building Plate

See table 3-25-20, table 3-25-2 1, table 3-25-22, table 3-25-23 and table 3-25-24 for the ministerial standard JC20S-83 of natural granite building board.

Table 3-25-20 Allowable Tolerance of Natural Granite Plate Specifications

Table 3-25-2 1 Allowable deviation of flatness of natural granite plate

Table 3-25-22 Allowable Angle Deviation of Natural Granite Plate

Note: ① The allowable deviation of the angle is the same as that of the rough grinding and polishing of the plate when the planer trims the plate mechanically; (2) Hand-chiseling, and the allowable deviation of the angle is the same as the chopping board; (3) The angle of the special-shaped plate is only allowed to have negative tolerance, and the deviation is subject to the side length of the included angle, as shown in Table 3-25-22.

Table 3-25-23 Allowable Range of Angular Defects of Natural Granite Plate

Note: ① The perimeter is less than 1m, and it is calculated as 1m if it is more than 0.5m. (2) The depth of bottom edge defects shall not exceed 1/3 plate thickness.

Table 3-25-24 Allowable Range of Natural Granite Plate

Note: areas smaller than 15mm× 15mm are not considered as spots.

Verb (abbreviation of verb) China decoration material market

China has a long history of developing and utilizing stone materials, and there are countless buildings built with granite and marble in past dynasties. Especially since 1978, with the development of domestic construction market and foreign trade, the demand for decorative stone materials has increased rapidly, which makes the development and utilization of marble and granite develop rapidly. Especially in recent years, the amount of stone mining has increased sharply, from 1993 to 1000 m3 to 1998, reaching 4.8 million m3, an increase of 4.8 times in five years. As a result, the supply of stone products exceeded demand, and the price of stone fell. The average price of 1999 is 30% ~ 40% of 1993, which is the lowest point in history. For example, the average 250 yuan /m2 of black granite has dropped to about 100 yuan /m2, and the enterprise has fallen from high profit to loss. At present, the price of stone has bottomed out and is expected to rebound. Although the market price is low, the price of high-grade varieties is still high. For example, the current price of high-grade Fengzhen Black is 260 ~ 300 yuan /m2. Other popular varieties are Jinan black (75 yuan/m2), mongolia black (120 yuan/m2), fuding black (80 yuan/m2) and Yexue (130 yuan/m2). The price of green granite plate is moderate, mostly between 150 ~ 300 yuan /m2, and the highest is about 380 yuan /m2.

Although China's stone industry has made great progress, compared with the world's advanced level, there is still a big gap in stone processing equipment (including general equipment, large equipment and special equipment), product varieties and technology. Table 3-25-25 lists the comparison of main machinery and equipment in stone industry between China and Japan. China is rich in marble and granite resources with many high-grade varieties. It is necessary to make rational development and utilization, from rough machining to finish machining, to improve product grade and enhance market competitiveness.

Table 3-25-25 Comparison of Main Mechanical Equipment in Stone Industry at Home and Abroad

Main references

[1] Editorial Committee of Handbook of Nonmetallic Mining Industry, Handbook of Nonmetallic Mining Industry, Metallurgical Industry Press, 1992.438+02.

Luo Xingmin, Pu Yong, Overview of Red Granite Resources in China, Non-metallic Minerals, 2000.3, pp. 43-45.

[3] Luo Xingmin, Pu Yong, Green Granite Resources and Non-metallic Minerals in China, June 2000, pp. 40-42.

[4] Pu Yong, Luo Xingmin, Black Granite Resources and Non-metallic Minerals in China, 2000.4, pp. 38-40.

[5] Fu Yonghua, Impression of local stone industry in Osaka, Japan, nonmetallic minerals, 1999.2, pp. 45-46.

[6] Zhao Laishi et al., Characteristics and Exploitation of "Shanxi Black" Granite Resources in Hunyuan, Non-metallic Minerals, 2000.438+0, pp. 45-47.