According to the national standard of Chinese stone classification, the stone is divided into five categories: marble, granite, travertine, sandstone, slate
In practical applications, the following types of stones are often used
1. Limestone
2. Quartzite (its material is hard, the pattern is special, and it is often used as the background wall of wealth fortune)
3. Semi-precious stones (because of their scarcity and preciousness, they are often used in the construction of high-end villas and even palaces)
Let’s introduce an ordinary stone.
1. Granite
Granite is an igneous rock, formed by underground magma eruption and intrusive cooling crystallization, as well as granitic metamorphic rocks. It has a visible crystal structure and texture. It is composed of feldspar (usually potash feldspar and austenitic) and quartz, mixed with a small amount of mica (biotite or muscovite) and trace minerals, such as zircon, apatite, magnetite, ilmenite, And sphene, and so on. The main component of granite is silica, the content of which is about 65%-85%. The chemical properties of granite are weakly acidic. Under normal circumstances, granite is slightly white or gray, because it is mixed with dark crystals, the appearance is spotted, and the addition of potassium feldspar makes it red or flesh-colored. Granite is formed by magma slowly cooling and crystallizing, and it is buried deep below the surface. When the cooling rate is abnormally slow, it forms a kind of granite with a very rough texture, which is called crystalline granite. Granite and other crystalline rocks form the basis of continental plates, and it is also the most common intrusive rock exposed on the earth’s surface.
Although granite is considered to be an igneous rock formed from melted material or magma, there is ample evidence that some granites are formed by local deformation or the product of previous rocks that have not undergone liquid or melt processes to rearrange and recrystallize.
The specific gravity of granite is between to and its compressive strength is 1,050 to 14,000 kg/cm² (15,000 to 20,000 PSIG). Because granite is stronger than sandstone, limestone, and marble, it is more difficult to mine. Due to the special conditions and firm structural characteristics of granite formation, it has the following unique properties:
(1) It has good decorative performance and can be applied to public places and outdoor decoration.
(2) Excellent processing performance: sawing, cutting, polishing, drilling, carving, etc. The machining accuracy can reach 0.5μm or less, and the luminosity can reach over 1600.
(3) Good wear resistance, 5-10 times higher than cast iron.
(4) The coefficient of thermal expansion is small, and it is not easy to deform. It is similar to indium steel and is minimally affected by temperature.
(5) The modulus of elasticity is large, higher than that of cast iron.
(6) Good rigidity, large internal damping coefficient, 15 times larger than steel. It is shockproof and shock-absorbing.
(7) Granite is brittle, and only partly falls off after being damaged, without affecting the overall flatness.
(8) Granite has stable chemical properties, is not easy to weather, and is resistant to acid, alkali, and corrosive gases. Its chemistry is proportional to the content of silica, and its service life can reach about 200 years.
(9) Granite is non-conductive, non-magnetic, and stable in the field.
Generally, granite falls into three different categories:
Fine-grained granite: The average diameter of feldspar crystals is 1/16 to 1/8 inch.
Medium-grained granite: The average diameter of feldspar crystals is about 1/4 inch.
Coarse-grained granite: The average diameter of feldspar crystals is about 1/2 inch and larger diameter crystals, and some even reach several centimeters. The density of coarse-grained granite is relatively low.
In recent years, granite accounts for 83% of the stone materials used in monument construction, and marble accounts for 17%.
2. Marble
A marble is formed from sedimentary rock and metamorphic rock of sedimentary rock. It is a kind of metamorphic rock formed after the recrystallization of limestone, usually accompanied by the texture of biological remains. The main ingredient is calcium carbonate, the content of which is about 50%-75%, which is weakly alkaline. Some marbles contain a certain amount of silica, and some do not. The particles are fine and fine (referring to calcium carbonate), the surface stripe distribution is generally irregular, and the hardness is low. The composition and structural characteristics of marble make it have the following properties:
(1) Good decorative performance. Marble does not contain radiation and is bright in color and rich in colors. It is widely used for interior wall and floor decoration. Has excellent processing performance: sawing, cutting, polishing, drilling, carving, etc.
(2) Marble has good abrasion resistance and is not easy to age. Its service life is generally about 50-80 years.
(3) In industry, marble is widely used. Such as: used in raw materials, cleaning agents, metallurgical solvents, etc.
(4) Marble has the characteristics of non-conductive, non-magnetic, and stable field position.
From a commercial point of view, all naturally occurring calcareous rocks that can be polished are called marbles, as are certain dolomites and serpentinites. Because not all marbles are suitable for all architectural occasions, marbles should be divided into four categories: A, B, C, and D. This classification method is particularly suitable for relatively brittle C and D marbles, which require special treatment before or during installation.
The specific classification is as follows:
Class A: High-quality marble with the same and excellent processing quality without impurities and pores.
Type B: The characteristics are similar to the previous type of marble, but the processing quality is slightly worse than the former; there are natural flaws; a small amount of separation, gluing, and filling is required.
Type C: There are some differences in processing quality; defects, pores, and texture breaks are more common. The difficulty of repairing these differences is moderate, and it can be achieved by one or more of these methods of separation, gluing, filling, or reinforcement.
Class D: The characteristics are similar to those of Class C marble, but it contains more natural flaws and the difference in processing quality is the biggest. It requires multiple surface treatments with the same method. This kind of marble affects many colorful stones, and they have good decorative value.
3. Limestone
Limestone is a kind of rock formed by a sedimentary source. The main component is calcium carbonate, calcium magnesium carbonate, or a mixture of calcium carbonate and magnesium carbonate. Recrystallized limestone, strong microcrystalline limestone, and polishable travertine are all advertised and sold as limestone or marble, especially in the United States. According to different density ranges, formed limestone is divided into three sub-categories:
Low-density limestone-the density range is 110-135 pounds/cubic foot (1,760-2,160 kg/cubic meter).
Medium-density limestone-the density range is 135-160 pounds/cubic foot (2,160-2,560 kg/cubic meter).
High-density limestone-density greater than 160 pounds/cubic foot (2,560 kg/cubic meter).
Limestone has many distinctive natural characteristics, such as calcite patterns or spots, fossil or shell structures, potholes, elongated tissues, open textures, honeycomb structures, iron spots, travertine-like structures, and crystal differences. The combination of one or more of the above characteristics will affect the texture of limestone.
4. Slate
Slate is also a kind of sedimentary rock. The shale that formed the slate was first deposited on the soil bed. Later, the movement of the earth made these shale beds layer up. The intense metamorphism caused the shale bed to fold and shrink and finally turned into a slate. The main component of slate is silica. Its characteristics are acid-resistant.
According to the composition of slate, slate can be divided into three types:
(1) Carbonate-type slate: its component silica content is less than 40%, aluminum oxide content is less than 10%, calcium oxide content is less than 15%, magnesium oxide content is less than 10%, and iron oxide content is 3 %—7%.
(2) Clay-type slate: its composition is mainly sericite, illite, chlorite, kaolin, and other clay minerals, which account for more than 80% of the mineral composition of slate, and its silica content is greater than 50%. The aluminum content is greater than 12%, the calcium oxide content is less than 10%, the magnesium oxide content is less than 5%, and the iron trioxide content is higher than that of carbonate type slate.
(3) Carbonaceous and siliceous slate: The mineral composition is between clay-type slate and carbonate-type slate. Due to the strong degree of silicification, high silica content, the stone is quite hard and the color is darker.
The structure of the slate is flaky or massive, with fine grains. The grain size is between 0.9 and 0.001 mm. It is usually a cryptocrystalline structure, relatively dense, and most of them are oriented. The cleavage of the rock is well developed and the thickness is uniform. Moderate hardness, low water absorption. Its life span is generally about 100 years.
The color of the slate is mostly monochromatic. Such as gray, yellow, green-gray, green, cyan, black, maroon, red, fuchsia, etc. Because the color is single and pure, it gives a sense of elegance and elegance in terms of decoration. The slate is generally no longer polished, showing a natural shape and forming a natural beauty.
Therefore, sandstone and slate have better colors than marble and granite, and their decoration is often used in places with rich cultural connotations.
5. Sandstone
Sandstone, also known as sandstone, is a kind of sedimentary rock formed due to the crustal movement of the earth, sand, and cement (siliceous matter, calcium carbonate, clay, iron oxide, calcium sulfate, etc.) are compressed and bonded by long-term huge pressure.
main ingredient:
A. Quartz content above 65%
B. Clay around 10%
C. Goethite about 13%
D. Other substances more than 10%
The sand and gravel have uniform particles, fine texture, and loose structure, so the water absorption rate is high (the cost is higher during protection), and it has the characteristics of sound insulation, moisture absorption, resistance to damage, weathering, fading, insoluble in water, and no radioactivity. Sandstone cannot be polished. It is a matt stone and will not cause light pollution caused by light reflection. It is also a natural non-slip material.
In terms of decoration style, sandstone creates a warm-toned style, which is simple and elegant, warm without losing the luxurious atmosphere. In terms of durability, sandstone is absolutely comparable to marble and granite. It will not weather or change color. Many buildings made of sandstone a hundred or two hundred years ago still have the same style and charm. According to the characteristics of this type of stone, it is often used for indoor and outdoor wall decoration, furniture, sculpture art, and garden construction materials.
Among them, Aotian Aoli sandstone has uniform particles, fine texture, and ideal natural effect. Aotian Aoli sandstone is the hardest among all sandstone varieties. This also determines its durability.
There are four varieties of white sandstone, yellow sandstone, wood grain sand, and landscape grain sand.
use:
A: Interior and exterior curtain wall decoration, specification board, floor
B: Furniture, sculpture art, construction materials for pavement, and gardens.
C: Carved thread, embossed board, door cover, window cover, vase, Roman column, and other special-shaped processing.
Features: sandstone, sound insulation, moisture absorption, resistance to damage, outdoor weathering, insoluble in water, no moss, easy to clean, etc.
6. Quartzite
Quartzite is a common and widely distributed rock that is mainly or entirely composed of quartz. This dense, granular rock is a kind of metamorphic sandstone, in which silica or quartz is deposited in quartz particles as the basic component of the sandstone. Quartzite also contains traces of other minerals, such as feldspar, mica, rutile, tourmaline, and zircon. Quartzite has smooth cross-sections and is mainly buried deep in ancient rocks, such as Cambrian or Precambrian rock formations.
7. Roman stone
Roman stone is a rectangular block of (10～15mm)×(10～15mm)×(12～20mm) cut from natural granite by a cutting machine. Rome is the most used, also called Roman stone. This kind of stone must maintain a natural fracture surface after being cut, mainly in variegated colors, with eye-catching spots, which is a high-level one. Paving roads with Roman stone is very simple and natural, and it is also one of the methods of rational use of stone resources. It appears in the form of semi-circular splicing on the road, which is mostly seen around the streets and ancient buildings in ancient European cities. In recent years, it has also been applied to some cities in my country. There is not much technical basis for paving the road with a semicircle, and most of them are considered to be similar to the dome style that often appears in Western architecture and is popular.
Three, artificial stone introduction
Artificial stone, as the name implies, is not a stone made of 100% natural stone materials. According to the different production methods, it can be divided into two types: one is to grind the raw materials into stone powder, then add chemical agents, adhesives, etc., to make the board by high pressure, and add artificial pigments and imitating the original stone texture on the appearance color to improve Variety and selectivity. The other is called artificial granite. After crushing the rough stone, adding colloid and stone material to vacuum stirring, and using high-pressure vibration to shape it to form blocks of rock, which are then cut into building materials slabs; In addition to retaining the natural texture, it can also be selected in advance to unify the colors, add favorite colors, or embed glass, acrylic, etc., to enrich its color diversity.
Commonly used indoor decorative floor materials include granite, pearl scallops, and cultural stones. The hardness is not as hard as natural stone, and there are obvious texture differences. However, because its price is much lower than that of natural stone, it is becoming more and more popular, especially synthetic granite containing 90% natural rough stone, which overcomes the lack of natural stone that is easy to break and the texture is not easy to control. It retains the original flavor of natural stone and is in the global market. There is even a trend to use floor materials instead of marble and granite.
