From Latin “granite” is translated as “grain”. It is a granular volcanic massive rock that was formed during the process of gradual cooling and solidification of magma at a fairly large depth. In addition, its origin is possible during metamorphism, in other words, during the granitization of various rocks. Very often, granite massifs are attributed to igneous, metamorphic and mixed origin. Granite is the most common rock in the earth's crust.
Considering its characteristics, we can say that it is a very durable material, due to which it is very common in construction. One of the most important characteristics of the rock is its high strength.
Qualities
Granites are divided into:
- fine-grained;
- medium grain;
- coarse-grained.
If we consider a fine-grained stone, then the characteristics of this type of granite will be very different from the rest. This group resists mechanical stress much better. During use, it wears out more evenly, cracks less when heated, and is resistant to weathering.
This group is the most expensive and high quality. It is resistant to destruction, waterproof and highly durable. Coarse-grained samples are characterized by insufficient fire resistance. When heated above 600˚C, they begin to crack and increase in volume. Because of this, sometimes in houses after fires you can often see cracked granite stairs and steps.
Despite its excellent density and strength, the stone is easy to process: polished, ground and cut. It has excellent thermal conductivity, which is why it is often used for heaters.
Of course, the above characteristics are considered advantages of this material. But granite stone also has disadvantages. The main disadvantage is its heavy weight, due to which it is one of the heaviest finishing materials. This characteristic must be taken into account when creating construction projects.
Structural and chemical composition
Granite is a rock that has a granular-crystalline structure. It is enriched with alkalis, rich in silicic acid, and contains iron, magnesium and calcium in smaller quantities.
The composition of the mineral in its average values:
- feldspars - 60-65%;
- quartz - 25-30%;
- dark-colored minerals - 5-10%.
The color of the rock primarily depends on the nature of the feldspars present in the composition. Most often its color is gray with various shades: red, pink, gray-blue, orange, and sometimes bluish-green.
In addition, dark-colored components influence the formation of the shade. These elements often give the breed a dark color, usually greenish. An example of this is Yantsevsky granite.
But quartz is most often colorless, therefore, it does not affect the nature of the color. At the same time, sometimes you can find a mineral with black quartz, less often - lilac-pink. Blue quartz minerals are considered very rare. The most decorative characteristics are found in fine-grained light gray samples with a blue tint. In addition, blue-green and red granite are in great demand.
Appearance
As mentioned above, the mineral is actively used in construction. And this is easy to explain. Granite is an igneous rock that is highly polished. The resulting mirror surface is preserved for a long time even if the material is used in external cladding.
The stone is also easy to process and easily takes on different shapes. The relief texture of the granite surface emphasizes the monumentality of buildings and gives a decorative, interesting effect of play of chiaroscuro.
At the same time, some types of stone receive decorative texture only after heat treatment. This applies mainly to light gray shades, which after processing become almost sugar-white.
Place of Birth
The main form of occurrence is considered to be batholiths. They represent a large massif with an area of several hectares. Most often, the rock occurs in the form of stocks, dikes and other intrusive bodies. Sometimes the mineral forms several sheet-like bodies, alternating with metamorphic and sedimentary rocks.
Granite is found on each of the continents. It mainly comes to the surface in those areas that were composed of ancient rocks, where, due to the erosion-denudation process, the overlying sediments were destroyed.
Thus, in the United States, this breed is found in the north of the country, along the coast of the Atlantic Ocean, in the Black Hills and the center of the Ozark Plateau. The stone is mined in Georgia, Wisconsin, South Dakota and Vermont.
It is also common in our country. About 200 granite deposits are exploited in the post-Soviet space. The largest of them are: Mokryanskoye, Malokokkhnovskoye, Mikashevichi.
On the territory of the Russian Federation, granite is most common in the Karelo-Kola region, Eastern Siberia, the Urals, the Far East and the Caucasus. Today, about fifty deposits are known in which the piece mineral is mined. Granite crushed stone and rubble are mined in the Ladoga region, the Onega region, in the Arkhangelsk and Voronezh regions, on the Karelian Isthmus, in the Chelyabinsk and Sverdlovsk regions, in the Khabarovsk Territory and Primorye, in Eastern Transbaikalia. Rapakivi mined in the north-west of the country has excellent decorative characteristics; in addition, amazanites from Transbaikalia and the Ilmen Mountains are also valued. Many deposits do not operate continuously, mainly for crushed stone and rubble. In them, as necessary, granite blocks are mined and facing slabs are made from them.
There are several types of granite, we will look at them in the article below.
Gabbro-diabase
This is a durable, homogeneous mountain granite of a black hue, with small inclusions of gray. It perfectly accumulates and then releases heat, heats up evenly throughout the entire mass, and does not lose its polishing quality and artistic properties for the longest period of time.
This stone is considered a 1st class building material. It does not emit any harmful impurities and is completely non-radioactive. At the same time, Karelian gabbro-diabase is a unique rock that has no analogues in other regions of our country.
The mineral is used for the production of road block stones (mosaic block, pavement paving stones, curbs), for the manufacture of interior items and various ritual products, in precision engineering, for landscape design, as a plinth stone in construction. Ideally suited for interior decoration and cladding of building facades, partially used for crushed stone and rubble, and used for heaters in saunas and baths.
There are 3 main areas for block stone mining in the world:
- Ukrainian gabbro-diabase, which is inferior in quality to Karelian, although almost half the price. It contains a huge number of iron impurities, and this deteriorates the quality of the finished products, while the design applied to the stone quickly fades.
- Australian gabbro-diabase, similar in quality to Karelian, although much more expensive.
- Karelian gabbro-diabase, which has a black color, a low degree of abrasion, high decorative properties, durability, frost resistance, and retains the design applied to it for a long time.
Based on the ratio of quality and price, Karelian gabbro-diabase is usually in higher demand. At the same time, it is steadily increasing every year. The popularity of using the Karelian mineral is explained by its durability and strength. This stone is almost not subject to negative environmental influences. It retains its properties much longer than marble, and the very first signs of destruction appear only after a hundred years.
"Chansi Black" (Chinese granite)
Chinese granite is a black rock considered one of the best in the world. It is mined in northern China, in the Shanxi province. Its main advantage is its rich and deep black color with a small amount of inclusions. It is used for cladding facades, interior decoration, manufacturing products for various purposes, memorials and monuments.
Shoksha
This crimson granite, the price of which is very affordable - about 10,000 rubles / ton, is mined in the Republic of Karelia. It is durable and highly durable. Experts say that products made from it will not lose their shape for more than 600 years. He decorated mausoleums, palaces, and monuments. The inscriptions and the engraved portrait on the shoksha look contrasting.
"Kapustinsky" granite
This is an uneven and coarse-grained, pink-red, bright, massive, highly decorative granite, reviews of which speak of its incredible beauty. The area of use is suitable for the production of pedestals, as well as for other architectural structures, for finishing elements of structures and buildings, in places where high architectural expressiveness is required. It was used in the decoration of the Temple of Memory, located on Poklonnaya Gora, Manezhnaya Square. There is a deposit in the Kirov region, Ukraine.
Labradorite
It is a natural stone, which is a mountainous granular-crystalline rock. Labradorites appear in igneous depths. They are mainly composed of plagioclase, which is a feldspar. The structure of minerals is crystalline. It is divided into medium-grained and coarse-grained rocks.
Labradorites are a type of anorthosite. They got their name from their original deposit - this is the name of the peninsula in Canada. Today, the extraction of this natural stone occurs in other countries, including Ukraine and Finland. There are also large deposits in Russia. The first mineral structures were found in Kievan Rus - then this granite was used exclusively, then they began to decorate monumental buildings.
Mostly this granite is gray or black. Dark-colored minerals give the stone a beautiful dark shade. The main properties of labradorites are their frost resistance and high strength. Consequently, these stones are most often used for exterior decoration of buildings.
In addition, granite is distinguished by its structural and textural properties.
Porphyritic
This Ural granite contains elongated or isometric inclusions, which differ in size from the main mass (can reach 10 centimeters). Typically represented by orthoclase, quartz and microcline.
Pegmatoid
This is a granitic rock with a uniform characteristic grain size. The size of inclusions and quartz is about 3 centimeters.
Finnish granite
This granite is an igneous rock with characteristic round numerous inclusions of red orthoclase up to five centimeters in size, surrounded by a border of gray-green or gray oligoclase. The main mass in it is an aggregate of grains of orthoclase, plagioclase, hornblende, quartz and biotite.
Gneissic
This Ural granite is a uniformly fine-grained ordinary stone with a characteristic roughly parallel orientation of grains or mica flakes.
Pegmatite granite
One of the most common varieties is pegmatite granite, consisting of muscovite, quartz and orthoclase. A characteristic representative of this variety is the so-called written granite, in which feldspar grows with small formations of thin wedge-shaped quartz.
Leznikovsky granite
Red and pink-red Leznikovsky granite, which received its name from the name of its deposit, is particularly durable and popular. It should be noted that many types of granite are named this way. For example, Mezhdurechensky, Simonovsky, Tokovsky, Emelyanovsky, Kapustinsky. But gray granite can be Korninsky, Pokostovsky, Zhezhelevsky, Sofievsky.
Rapakivi
Another interesting variety of the mineral is rapakivi. It is a porphyritic formation with a huge content of ovoids.
White granite
White granite is also available. Not everyone can immediately answer which mountain. This concept is more collective, since both snow-white stones and other light-colored minerals are called white. Color can vary from pearl gray to light green.
Application
In today's construction, granite is so actively used that it can be called a truly universal material.
Interior details
Cornices, window sills, railings, baseboards, countertops, bar counters, coffee tables, columns, balusters - the high strength of the stone will allow you to order these products from granite, and they will remain undamaged for many years.
Stairs, floors
Granite is a material with a low degree of abrasion. If a million people walk up the stairs in your apartment in a year, they can erase the steps by a maximum of 0.12 millimeters.
Interior and facade finishing
Granite is a very ergonomic material that can provide you with a completely comfortable stay in the building.
Landscape design
Rock gardens, alpine hills, decorative ponds, Japanese gardens made of granite will add uniqueness and naturalness to your site.
Curbs, paving stones, steps
Granite is used successfully in places where enormous “endurance” is required. The mineral is resistant to chemical pollution, mechanical stress, and temperature changes, since it does not change its properties over many cycles of thawing and freezing.
Facing embankments
Granite almost does not absorb moisture, which means that in the pores of the stone, when the temperature drops from frozen water, internal additional pressure does not form, which can lead to destruction of the rock and the formation of cracks.
Granite paving stones
The use of paving stones from this stone dates back thousands of years. You can still walk along the famous ancient Roman paved roads; you can find cobblestone streets in the old part of every European capital; in the modern world, when processing granite by craftsmen does not cause any difficulty, stone roads are also gradually replacing concrete and asphalt.
Magic properties
It may seem at first glance that granite, the photo of which is presented in this article, does not have any magical properties, since in modern apartments and houses it is actively used for interior decoration, which means it has only an aesthetic component. But there is evidence that this mineral is capable of making a person’s life better.
In ancient times, bathhouses were built from granite. It has always been the cleanest place in which a person could relax. Here we are talking not only about the attractiveness and external gloss of the stone, but also about the fact that the mineral can protect a room and a person from negative energy.
There is a well-known phrase: “Gnawing on the granite of science.” It did not come into use by chance. Granite (which rock is meant is not important) has the properties of stimulating communication and mental activity.
Red granite helps a person find mutual understanding with the world, increases his intuition, while making its owner more responsive and flexible.
Medicinal properties
Granite, a photo of which can be seen in our review, has a wide range of healing properties that can alleviate various serious diseases. Among them are pneumonia, asthma, cardiovascular diseases, and bronchitis.
The stone for colds helps reduce temperature and has a positive effect on the spine and joints when there are problems with them.
Mascot
Granite is the best talisman for people who have dedicated their lives to pedagogy or science. The mineral sharpens intuition, strengthens memory, develops rational thinking, etc.
Granite products can be excellent amulets for teachers and teachers; they can help find an approach to stubborn and difficult students, as well as gain authority with them.
Granite is a mineral with unconditional positive energy that does not harm anyone, therefore, you should not be afraid of it.
Granite: reviews
Since granite is very popular in construction, where, by the way, it has been used for hundreds of years, it is not difficult to find reviews about it. Almost everyone who has had to deal with this wonderful material admires its high strength and excellent characteristics. Others are somewhat intimidated by its cost. But in this case, you need to take into account that different types of mineral may have different prices. Therefore, you can always choose the right option for yourself.
Granite is a deep, acidic, intrusive (underground) igneous rock with a granular structure. The grain sizes range from a few fractions of a mm to several cm in diameter. The main molecules of granite are potassium feldspars, acidic plagioclase and quartz, and a small amount of dark-colored minerals. Intrusive mountain granite is the most common.
What is granite made of?
The main rocks that are present in granite: feldspars are the most common rock-forming minerals, accounting for over 50% of the mass of the earth's crust. Feldspars are classified as aluminosilicates with a framework structure. According to their chemical composition, feldspars are divided into 4 groups: plagioclase, potassium, potassium, and potassium-barium.Feldspars can be represented in various colors:
- white
- grey
- yellow
- pink
- red
- green
Quartz is a rock-forming mineral with a framework structure. Characterized by transverse hatching on the faces of the prism. It is one of the most common minerals in the earth's crust. A variety of chalcedony, amethyst, morion. Quartz is usually found in erupted rocks called rhyolites. Quartz is used in instrument making and optics as a semi-precious stone. Quartz can have different colors: colorless, white, gray, brown, pink. The density of quartz is about 2.5 - 2.6 g/cm3. It is classified as piezoelectric - that is, when deformed, it is capable of inducing an electric charge.
Mineralogical composition of granite.
Granite includes a wide range of minerals. Acid plagioclase is rock-forming minerals, aluminosilicates from the feldspar group. Plagioclases are a series of extreme member minerals, which are albite Na(AlSi3O8) abbreviated Ab and anorthite Ca (Al2Si2O8) (abbreviated An). Typically, the composition of the rock is designated by a number corresponding to the anorthite content as a percentage. Albit No. 0 - 10; oligoclase No. 10 - 30; andesine No. 30 - 50; Labrador No. 50 - 70; bitovnit No. 70 -90; anorthitis No. 90 - 100.
Primary colors of granite. What determines the color of granite?
Minerals that make up rocks can have different colors. This is explained by the mineral composition of which the rock is made. So if Si, Al, K, Na are present in the rock, then they will be colored in light colors (quartz, muscovite, feldspars). And if Fe and MgCa are present in the rock, then they will have a dark color (magnetite, biotite, amphiboles, pyroxenes, olivines).
Color range of minerals
What rocks form granite?
Granite is a material that was formed from igneous rocks. Igneous rocks are formed when cooling magma hardens both underground (intrusive) and on its surface (effusive). According to the alkali content, igneous rocks are divided into rocks of the normal series (that is, the ratio of the sum of alkalis to the alumina content<1) , щелочного ряда (отношение >1). According to the silica content, SiO2 can be acidic (silica from 67 to 75%), moderately acidic (from 67 to 52%), basic (from 40 to 52%) and ultrabasic (<40%)
What is granite made of?
Granite is a material that is used in the construction industry. But in order to use it, it must be processed and given certain sizes and shapes. After processing, this product is called crushed stone. can have different sizes, starting from 1 mm and ending with 120 mm (rubble stone). Crushed stone can also be classified according to shape, that is, according to the content of cuboid-shaped grains. The cuboid shape of crushed stone directly characterizes the level of adhesion to the binder components in the solution. The higher the cubicity index, the lower the consumption of crushed stone and other materials, since it is more compact, which means there will be slight shrinkage, and therefore the structure will have increased rigidity. One of the types of products obtained is granite screenings or
The formation of granite and faceted soil in general is still not fully understood. The strength of the rock is such that just 1 cm² of it can withstand a 600 kg load without consequences. This is 2600 kg/m³.
The formation of granite and faceted soil in general is still not fully understood
The amazing hardness of granite is up to 7 on the Mohs mineralogical scale. This hardness scale has 10 divisions and uses the scratch method. The density of granite is impressive: 1 cm³ weighs 3 times more than the same volume of water.
It cannot be said that all the physical properties of granite are impeccable. While withstanding temperature changes that are insane for humans of 100 degrees or more, it cannot boast of the same excellent refractoriness and melts when heated to 700 °C.
The low melting point of granite is the main reason why many ancient structures did not survive fires and were irretrievably lost.
Given this feature, subsequent generations of builders and architects still prefer to use all types of granite as a facing material. Frost-resistant, with a water- and dirt-repellent surface, it has a favorable price among materials for similar purposes.
Rock composition
What is this breed made of? The mineral composition of granite is based on minerals formed during the crystallization of magma, such as plagioclase, potassium feldspar, quartz, and mica. Granite derives its composition from igneous plutonic rocks of high acidity.
The basis of the earth's crust, its most important rock, is granite stone. However, how such minerals are formed is still not completely clear. There is an assumption that during the crystallization process, basaltic magma is gradually saturated with various chemical elements. Moreover, this process is subject to a certain pattern. At the end of this complex and long path, differentiates are formed - derivatives of a certain basaltic melt. The chemical composition of granite indirectly indicates the veracity of this assumption. After all, the rock is saturated with fusible sodium, potassium, and silicon.
The basis of the earth's crust, its most important rock, is granite stone
Stone has many faces. Its structure may be different. It can be fine-, medium- and coarse-grained. The finer the grain fraction (from 2 mm), the stronger the rock, the less susceptible it is to various atmospheric phenomena.
Gallery: granite stone (25 photos)
Color variations
Varieties of granite find different applications in areas of human activity. In many ways, color is decisive. It can be red, black, gray, beige, brown, bluish and even pink. Quartz and mica fragments in the composition give the stone, illuminated by the sun or artificial light, a sparkling appearance.
Granite gets its colors from the feldspars it contains.
Pink granite is also called amethyst for its shades from delicate to deep purple. Its deposits on Russian territory are in Karelia. And in Brittany there is Pleneuf-Val-André, the coast of which is called the Coast of Pink Granite for the unique delicate color of the boulders.
Varieties of granite find different applications in areas of human activity
Rich red slabs can be found in the decoration of buildings, bridges and embankments.
If the composition of the rock is dominated by black quartz, then the color of the granite is black. This variation is in great demand when constructing monuments, along with marble. Solemnly austere and at the same time radiating brilliance, such a stone looks stunning both in the form of a stele and as part of a composite monument.
Green color is rare. Gray is the most common in construction.
Stone of the Amazons
Amazonite granite among others looks magical. Its greenish-emerald hue looks perfect in jewelry boxes, snuff boxes, ashtrays and even beads embodied in stone.
The first deposit of this rock was discovered in Mongolia. But earlier it was also found in Scythian burial mounds in the form of jewelry, household items and even weapons. Herodotus and Pliny also associated this interesting name of the stone with the militant Amazons (from the Greek “amazon” - breastless).
The works of ancient scientists contain a description of these women who, worshiping the goddess of fertility, sacrificed their breasts to her. One of the legends puts forward the version that the use of granite by the Amazons made it possible to do without the brutal amputation of the right breast. Instead, warriors rubbed it with green amazonite powder from childhood. This, of course, is just a beautiful version, but it is not without scientific background.
The breed comes in shades from green to almost blue. This is a beautiful finishing and ornamental material.
Traces of tantalum and tin are often found in its composition. It is found on the Kola Peninsula and the Urals. Other mining sites are Madagascar's Antananarivo and Zimbabwe.
Which is better, granite or artificial stone (video)
Artificial or natural
Despite widespread mining, the properties and uses of natural granite do not always satisfy the goals of the end consumer. And price is not always the deciding factor. Although she is not small.
Artificial granite successfully solves problems that are difficult for natural granite. Products made from it look amazing.
It is difficult to call a stone unnatural: consisting of 80% natural granite chips, it is even outwardly indistinguishable from natural stone.
The characteristics of artificial granite differ little from the characteristics of natural stone. But the price differs noticeably.
The main advantage is the ability to form almost any shape specified by human imagination, because granite is formed from a viscous mass.
Its properties are somewhat inferior to the natural mineral. But a lot depends on the quality of the components and the integrity of the manufacturer.
It is sometimes difficult to distinguish between materials created by nature and man-made. There is only one characteristic of granite that will help you do this. Tap the surface with a metal object: if it is natural, the sound will be loud, and if not, it will be muffled.
How to determine quality
A brief description of a stone is usually not complete without mentioning possible cracks. But are they a marriage? Whatever the color of the minerals, the strength and durability of granite are determined by nature itself.
The ability to repel water and resistance to pollution, as well as numerous granite historical and architectural monuments with a history of several hundred years, allow us to assert that no minor natural defects in stones can affect their performance properties. The service life of granite products can reach up to 500 years.
The opinion about the radiation background of the rock, which can harm human health, is biased. The level of its radiation does not exceed the permissible level.
Granites are quite meltable. But hot kitchen utensils will never melt or damage a window sill or countertop made from this stone.
The stone is processed according to one or another scheme, depending on the purpose of the final product.
It is sawed, polished, ground, polished. Products are even made from cut granite.
Burching produces a grainy texture with an anti-slip effect. Imitation of natural chipping is widely used in the production of monuments.
Attention, TODAY only!
Have you ever looked at crushed stone that is used in construction or for backfilling railway tracks? These are usually quite beautiful small fragments of granular stone of a gray or reddish color.
The stone grains shine brightly in the sun, and it is noticeable that the structure of the mineral is quite heterogeneous and consists of particles of different colors. With a high probability we can say that the stone is one of the types of granite.
What is granite?
This rock is synonymous with hardness and strength. If they want to talk about something very durable, they say: harder than granite. Indeed, granite is the champion in hardness among rocks used in construction and decoration. Buildings erected from granite stand for hundreds, and sometimes thousands of years, surprising us with their beauty and durability. True, in ancient times this stone was rarely used for construction, since it was very difficult to process, especially by hand.
Even with the naked eye it is clear that granite contains particles of different rocks, i.e. its composition is heterogeneous. Even the name of the breed, which is derived from the Latin word, speaks about this "granum",meaning "grain, particle" .
Multi-colored grains form magnificent natural patterns, thanks to which granite is widely used for finishing private and public buildings, squares, memorial complexes, etc. High hardness and excellent frost resistance have made granite the most popular finishing rock, which perfectly withstands the harsh Russian climate.
Origin of granite
In nature, different types of granite were formed in two ways:
- from melted magma that cooled and crystallized deep in the earth’s crust under high pressure conditions, resulting in the formation of extremely hard and granular rock of high density;
- from a mixture of clastic and sedimentary rocks mixed with alumina, which, during tectonic processes, sank deep into the earth's crust and there were exposed to a complex of factors - high temperature, strong pressure and hot gases, which led to the sintering of particles of these rocks into a solid and durable conglomerate. 
The formation of granite occurred several million years ago. During this period, active mountain building processes were underway on our planet, earthquakes and rock layers were constantly occurring, rising to the surface, while others sank deep into the earth's crust.
Composition of granite
Different grades of granite contain many types of minerals, but most are based on a combination of quartz and feldspar in varying proportions, with additions of other minerals. The composition of granite can be approximately determined by the appearance of the grains:
- quartz - transparent or bluish, smoky-white crystals;
- gray and reddish grains - feldspar;
- transparent or black shiny plates - mica;
- potassium spar - cream or pinkish grains;
- oligoclase - yellow, greenish or bluish grains;
- plagioclase - pink grains.
Different types of granite can have a gray, reddish, pink, greenish or almost black color, numerous colored inclusions and small veins. The color scheme is determined by the minerals that are included in its composition.
Applications of granite
Despite its many excellent qualities, granite has found widespread use only in the last two hundred years, when a sufficient technological base for its processing appeared. The ancient and medieval world were content with softer marble and sandstone, and only relatively recently did cutting and grinding methods improve to such an extent that it became possible to quickly and efficiently process the hardest rocks.
Due to the almost complete absence of pores, granite is not saturated with water, so it can easily withstand numerous cycles of freezing and defrosting. This allows granite slabs to be used as external cladding of buildings and monumental structures, for paving streets and squares. 
Polished granite is also used in interior decoration: floors are laid out of it, stairs and columns are made, walls, pools, and bathrooms are lined with slabs. Countertops, window sills, bathtubs and sinks are cut out of granite, and sculptural compositions are made. But the largest amount of mined stone is crushed and used as crushed stone for backfilling roads, producing concrete and in construction work.
This is a stone of natural origin. It is mined in many places on our planet and there is a possibility that it is not found on other planets of the solar system. Therefore, granite is called “the calling card of the Earth” in different sources. This is one of the most durable breeds in the world. Granite contains most of the known minerals: feldspar, quartz, as well as mica formations of various origins.
Is granite a mineral or a rock? This question is often asked by people who are just beginning to be interested in geology and mineralogy. At its core, it is a rock. As already mentioned, it includes different minerals, and its composition is heterogeneous, in contrast to minerals (for example, quartz, amethyst, chrysolite), which are uniform in both structure and color.
The granite rock is ubiquitous in our lives: in the form of railway embankments, tombstones, wall cladding, street elements of decorated decorations. Granite products have long seemed to people the most common and familiar to the eye. Often we just pass by without focusing on how different this amazing stone can be. Those who wish can get to know it better: after all, few people think about what granite is made of and what the history of its origin is.
How did granite come about?
It is generally accepted that there are two natural ways by which this natural stone was formed. It could have arisen from molten magma (frozen volcanic lava). Deep in the earth's crust, magma slowly cools and turns into a fossilized structure, in which granite grains of different sizes crystallize over millions of years. It is no coincidence that its name itself comes from the Latin word “granum”, which means “grain”.
Natural stone granite is formed in nature in another way. Sedimentary rock, as well as clay-like sand and various types of stones, were gradually displaced through tectonic processes into the depths of the earth's crust. There, under the influence of high temperatures and pressure, substances melted and a process such as granitization.
Most granite formation occurs in so-called collision areas. Two continental plates collide with each other, causing an increase in the layer of crust on the continent. Many scientists believe that it is as a result of the thickening of the collision layers of the crust that layers of granite melt appear - at a depth of 10 to 20 km. This phenomenon is called granite magmatism . It is most typical for Andean batholiths, as well as for island arcs.
Where are granite deposits located?
The main place where granite occurs is the batholith mountain ranges, the length of which is about 4 km and the area of several hectares. Sometimes during mining it is clear that several layers of stone have been formed: granite and its sedimentary rock. The stone itself appears in the form of wide layers, alternating with representatives of sedimentary and metamorphic species.
Like other minerals that are not very rare, granite has become widespread almost everywhere: it can be found on any continent . Due to the fact that over millions of years, ancient rocks gradually displaced younger formations to the top, it came to the surface and became available for mining.
Chemical and mineralogical composition
As already mentioned, granite is a stone that has a granular structure in the form of crystals. The chemical formula of granite is represented by such basic elements as iron, calcium, magnesium and various alkalis.
Its main components are quartz, dark-colored minerals and feldspar. Spar provides certain shades, and if the stone has a lot of translucent grain, it means it contains a lot of quartz.
Depending on what rocks are included in a particular stone, the mineralogical composition of granite can be different. For example, if it is dominated by plagioclase and has little feldspar, it is called plagigranite. If, on the contrary, there is more feldspar in the stone and less dark flowers, this is Alaskan.
The chemical composition of the rock has the following scheme:
- content feldspars(orthoclase and plagioclase) - from 60 to 65%;
- quartz, providing high strength indicators - from 25 to 30%;
- dark colored minerals granite - from 5 to 10% (mostly biotites).
Depending on which feldspars are included in the composition of the stone, its color will also change. The most common is gray, on which different shades can appear: blue, pinkish, red, less often greenish. The color also depends on what is included in the composition of granite from dark-colored minerals. If searchers come across a rock consisting of biotite or hornblende, the stone will be painted in dark tones. There is a rather rare species called Yantsevsky, which has a pronounced shade of greenish color.
Properties
Granite is a rock that is distinguished by its enviable strength, which is why it has been used in construction since ancient times. The stone lasts a very long time, is resistant to rain and wind, and can withstand any climatic conditions. Few people know that the pyramids in Egypt are partially made of granite blocks. It was from this stone that many structures were built in India and ancient Rome. It is processed and polished quite easily, and the degree can be increased to the point that the surface of the slab even becomes mirror-like.
Compared to marble, this material twice as strong due to the fact that granite contains quartz. During this time, diamond drills are used. It is known that, despite its beauty and splendor, marble is very sensitive to temperature changes, which cannot be said about granite: it perfectly maintains its performance in the harshest conditions . Due to its durable structure, the stone susceptible to fungal attack much less than other materials .
The level of moisture absorption in the rock is low: the fine-grained structure of granite plays a key role in this. If it is denser, we are talking about a breed with the best properties. They depend on the origin of the granite. The origin of the stone, in turn, determines the depth of its occurrence, which affects its density and strength.
The fact that granite is one of the most durable materials, and its performance is always at the proper level, is largely ensured by the fact that it hardly absorbs moisture . This was the main reason for using stone to decorate embankments. By the way, the vast majority of the granite banks of the Neva were built under Peter I, which once again confirms the durability of granite.
Geochemical classification of the White and Chappell granitoids
For the convenience of designating one or another type of granite stone, in the mid-70s of the last century, a brief analysis of granitoids was made based on their most common types.
In this analysis, four types of stone were identified - S, I, M, A:
- Sedimentary (S)- the stone is the result of the melting of metasedimentary rocks;
- Igneous (I)- product of melting of substrates from metamagma;
- Mantle (M)- a stone formed from magmas, which include tholeiitic and basaltic rocks.
The chemical composition of granite S is close to granitoids I in most elements, with the differences being that S stones contain little calcium and sodium. Later classification appeared type A type of granite , differing in composition from subalkaline stones and consisting of a large number of incoherent chemical elements.
Classification of granitoids by grain structure
The size and structure of grains differ from one another to different types of stone.
Based on this, granite comes in the following types:
- if the grain size does not exceed 2 mm - fine-grained;
- grain size up to 5 mm - medium grain ;
- coarse-grained type - more than 5 mm.
A fine-grained stone will have the highest level of resistance to mechanical damage. It is characterized by more uniform abrasion over time, resistance to winds and high temperatures. The fine-grained fraction is always the most expensive. It practically does not absorb water and is highly resistant to fire.
When building houses, coarse-grained granite is often used. It is cheaper, so after fires you can often see granite stairs that have cracked and are no longer usable.
Names of granite based on mineral composition
Depending on what the main mineral composition of granite is, different types of stones are called differently:
- does not contain dark-colored minerals - Alaskan;
- with a low content of dark flowers - leucogranite;
- biotite- if this mineral in the composition of granite is from 6 to 8%;
- if the stone contains biotite and muscovite at the same time - double mica granite ;
- if the stone contains lithium mica - it is lithium fluoride granite ;
- with a high content of alkaline components - simply alkaline type of granite ;
- a rare species consisting of orthoclase, quartz rocks and augite - pyroxene.
Varieties of granite based on its structure
The structure of stone grains also varies.
Below are the main types of granite, named based on the structure of its grains:
- Porphyritic- characterized by brightly eye-catching long inserts. They differ from the main mass of the stone in that they protrude from it. These are quartz, orthoclase, microcline.
- Pegmatoid granite - characterized by a symmetrical and uniform level of grain.
- Rapakivi- a Finnish type of stone with rounded inserts (red with a gray or gray-green frame).
- Gneissic- the most common stone with a fine-grained structure.
Of course, for a person who first encounters the fact that there are a lot of varieties of granite, it can be difficult to figure out which one is the best. It all depends on the purpose for which you plan to use this material. There are a lot of application options, and the quality and reliability of granite is much higher than that of the more popular marble.
It is known that marble quickly darkens and deteriorates under the influence of temperature changes and high humidity, and granite will stand for a very long time without changing either the structure or the original color of the stone. In addition, for lovers of white stone, there are special types of granite, which, when properly processed, are indistinguishable from marble at first glance.
Thanks to the excellent performance characteristics of granite, which have proven themselves over many centuries, it is always possible to use it as a reliable building material, as well as for decorative elements. Since any product made from this stone is unpretentious to use, this stone does not require special care. It will withstand any weather and will serve for centuries.
The only disadvantage of granite is that among building materials it has the greatest weight, which must certainly be taken into account when designing bridges, monolithic houses and other large structures.