Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Granite shopping experience:

1. Compare - without doubt the biggest advantage that the Granite offers shoppers today is the ability to compare thousands of Granite at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.

2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about

3. Testimonials - don't know anybody that has bought a Granite? Wrong! If the Granite is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.

4. Questions - Got a question about Granite then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....

5. Reputation - Never heard of the company selling Granite? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Granite and build up a picture of their reputation for sales, returns, customer service, delivery etc.

6. Returns - still worried that even after all of the above your Granite wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.

7. Feedback - happy with your Granite then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.

8. Security - check for the yellow padlock on the Granite site before you buy, and the s after http:/ /i.e. https:// = a secure site

9. Contact - got a question about Granite, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.

10. Payment - ready to pay for your Granite, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.

, valley of the Merced River. The quarrying consists of splitting up the blocks

Granite (International Phonetic Alphabet: ) is a common and widely occurring type of Intrusion (geology), felsic, igneous rock rock (geology). Granites are usually medium to coarsely crystalline, occasionally with some individual crystals larger than the groundmass forming a rock known as Porphyry (geology). Granites can be pink to dark gray or even black, depending on their chemistry and mineralogy. Outcrops of granite tend to form tor (geography), and rounded massifs. Granites sometimes occur in circular depression (geology)s surrounded by a range of hills, formed by the Metamorphism#Contact_(Thermal)_metamorphism or hornfels.

Granite is nearly always massive (lacking internal structures), hard and tough, and therefore it has gained widespread use as a construction stone. The average density of granite is 2.75 gcm−3 with a range of 1.74 gcm−3 to 2.80 gcm−3. The word granite comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a crystalline rock.

Mineralogy Granite is classified according to the QAPF diagram for coarse grained pluton (granitoids) and is named according to the percentage of quartz, alkali feldspar (orthoclase, sanidine, or microcline) and plagioclase feldspar on the A-Q-P half of the diagram. Granite-like rocks which are normative mineralogy may have a feldspathoid such as nepheline, and are classified on the A-F-P half of the diagram.

True granite according to modern petrology convention contains both plagioclase and alkali feldspars. When a granitoid is devoid or nearly devoid of plagioclase the rock is referred to as alkali granite. When a granitoid contains

Occurrence is a granite monolith in British ColumbiaGranite is currently known only on Earth where it forms a major part of continental crust. Granite often occurs as relatively small, less than 100 km² stock masses (stocks) and in batholiths that are often associated with orogeny mountain ranges. Small dike (geology) of granitic composition called aplites are often associated with the margins of granitic Intrusion (geology)s. In some locations very coarse-grained pegmatite masses occur with granite.

Granite has been intruded into the Crust (geology) of the Earth during all Geologic ages, although much of it is of Precambrian age. Granitic rock is widely distributed throughout the continental crust of the Earth and is the most abundant basement rock that underlies the relatively thin sedimentary rock veneer of the continents.

Despite being fairly common throughout the world, the areas with the most commercial granite quarry are located in Finland, Norway and Sweden (Bohuslän), Spain (mostly Galicia (Iberia) and Extremadura), Brazil, India and several countries in southern Africa, namely Angola, Namibia, Zimbabwe and South Africa.

Origin Granite is an igneous rock and is formed from magma. Granitic magma has many potential origins but it must intrude other rocks. Most granite intrusions are emplaced at depth within the crust, usually greater than 1.5 kilometres and up to 50 km depth within thick continental crust. The origin of granite is contentious and has led to varied schemes of classification. Classification schemes are regional; there is a French scheme, a British scheme and an American scheme. This confusion arises because the classification schemes define granite by different means. Generally the 'alphabet-soup' classification is used because it classifies based on genesis or origin of the magma.

Geochemical origins Granitoids are a ubiquitous component of the crust. They have crystallized from magmas that have compositions at or near a eutectic point (or a temperature minimum on a cotectic curve). Magmas will evolve to the eutectic because of igneous differentiation, or because they represent low degrees of partial melting. Fractional crystallization (geology) serves to reduce a melt in iron, magnesium, titanium, calcium and sodium, and enrich the melt in potassium and silicon - alkali feldspar (rich in potassium) and quartz (SiO2), are two of the defining constituents of granite.

This process operates regardless of the origin of the parental magma to the granite, and regardless of its chemistry. However, the composition and origin of the magma which differentiates into granite, leaves certain geochemical and mineralogical evidence as to what the granite's parental rock was. The final mineralogy, texture and chemical composition of a granite is often distinctive as to its origin. For instance, a granite which is formed from melted sediments may have more alkali feldspar, whereas a granite derived from melted basalt may be richer in plagioclase feldspar. It is on this basis that the modern "alphabet" classification schemes are based.

Alphabet Soup Classification The 'alphabet soup' scheme of Chappell & White was proposed initially to divide granites into I-type granite (or igneous protolith) granite and S-type or sedimentary protolith graniteChappell, B.W. and White, A.J.R., 2001. Two contrasting granite types: 25 years later. Australian Journal of Earth Sciences v.48, p.489-499.. Both of these types of granite are formed by melting of high grade metamorphic rocks, either other granite or intrusive mafic rocks, or buried sediment, respectively.

M-type or Mantle (geology) derived granite was proposed later, to cover those granites which were clearly sourced from crystallised mafic magmas, generally sourced from the mantle. These are rare, because it is difficult to turn basalt into granite via fractional crystallisation.

A-type or anorogenic granites are formed above volcanic "hot spot" activity and have peculiar mineralogy and geochemistry. These granites are formed by melting of the lower crust under conditions that are usually extremely dry. The granite of Yellowstone caldera is an example of an A-type granite.

Granitization An old, and largely discounted theory, granitization states that granite is formed in place by extreme metamorphism. The production of granite by metamorphic heat is difficult, but is observed to occur in certain amphibolite and granulite terrains. In-situ granitisation or melting by metamorphism is difficult to recognise except where leucosome and melanosome (geology) textures are present in gneisses. Once a metamorphic rock is melted it is no longer a metamorphic rock and is a magma, so these rocks are seen as a transitional between the two, but are not technically granite as they do not actually intrude into other rocks. In all cases, melting of solid rock requires high temperature, and also water or other volatiles which act as a catalyst by lowering the solidus (chemistry) temperature of the rock.

Ascent and emplacement The ascent and emplacement of large volumes of granite within the upper continental crust is a source of much debate amongst geologists. There is a lack of field evidence for any proposed mechanisms, so hypotheses are predominantly based upon experimental data.There are two major hypotheses for the ascent of magma through the crust: Of these two mechanisms, Stokes diapir was favoured for many years in the absence of a reasonable alternative. The basic idea is that magma will rise through the crust as a single mass through buoyancy. As it rises it heats the Country rock (geology), causing them to behave as a power law fluid and thus flow around the pluton allowing it to pass rapidly and without major heat loss (Weinberg, 1994). This is entirely feasible in the warm, Ductility lower crust where rocks are easily deformed, but runs into problems in the upper crust which is far colder and more brittle. Rocks there do not deform so easily: for magma to rise as a pluton it would expend far too much energy in heating wall rocks, thus cooling and solidifying before reaching higher levels within the crust.Nowadays fracture propagation is the mechanism preferred by many geologists as it largely eliminates the major problems of moving a huge mass of magma through cold brittle crust. Magma rises instead in small channels along self-propagating Dike (geology) which form along new or pre-existing Fault (geology) systems and networks of active shear zones (Clemens, 1997). As these narrow conduits open, the first magma to enter solidifies and provides a form of insulation for later magma.Granitic magma must make room for itself or be intruded into other rocks in order to form an intrusion, and several mechanisms have been proposed to explain how large batholiths have been emplaced:

Most geologists today accept that a combination of these phenomena can be used to explain granite intrusions, and that not all granites can be explained by one or another mechanism.

Natural Radiation Granite is a normal, geological, source of Particle radiation in the natural environment. Granite contains around 10 to 20 parts per million of uranium. By contrast, more mafic rocks such as tonalite, gabbro or diorite have 1 to 5 ppm uranium, and limestones and sedimentary rocks usually have equally low amounts.

Many large granite plutons are the sources for palaeochannel-hosted or roll front uranium ore deposits, where the uranium washes into the sediments from the granite uplands and associated, often highly radioactive, pegmatites.

In buildings constructed primarily from natural granite, it is possible to be exposed to approximately 200 Röntgen equivalent man per year. Lehigh University

Granite could be considered a potential natural radiological hazard as, for instance, villages located over granite may be susceptible to higher doses of radiation than other communites. Radiation and Life Cellars and basements sunk into soils formed over or from particularly uraniferous granites can become a trap for radon gas, which is heavier than air.

However, in the majority of cases, although granite is a significant source of natural radiation as compared to other rocks it is not often an acute health threat or significant risk factor. Various resources from national geological survey organisations are accessible online to assist in assessing the risk factors in granite country and design rules relating, in particular, to preventing accumulation of radon gas in enclosed basements and dwellings.

Uses Antiquity The Red Pyramid of Ancient Egypt (c.26th century BC), named for the light crimson hue of its exposed granite surfaces, is the third largest of Egyptian pyramids. Menkaure's Pyramid, likely dating to the same era, was constructed of limestone and granite blocks. The Great Pyramid of Giza (c.26th century BC) contains a huge granite sarcophagus fashioned of "Red Aswan Granite." The mostly ruined Black Pyramid dating from the reign of Amenemhat III once had a polished granite pyramidion or capstone, now on display in the main hall of the Egyptian Museum in Cairo (see Dahshur). Other uses in Ancient Egypt, include columns, door lintels, sills, jambs, and wall and floor veneer. How the Egyptians worked the solid granite is still a matter of debate. Dr. Patrick Hunt has postulated that the Egyptians used Emery (mineral) shown to have higher Hardenability on the Mohs scale of mineral hardness.

Many large Hindu temples in southern India, particularly those built by the 11th century king Rajaraja Chola I, were made of granite. There is a large amount of granite in these structures. They are comparable to the Great Pyramid of Giza.

Modern Granite has been extensively used as a dimension stone and as flooring tiles in public and commercial buildings and monuments. With increasing amounts of acid rain in parts of the world, granite has begun to supplant marble as a monument material, since it is much more durable. Polished granite is also a popular choice for kitchen countertops due to its high durability and aesthetic qualities. Image:Granite azul noce.jpg])Image:Granite giallo.jpg|Santa Cecelia(Brazil)Image:Granite_gran_violet.jpg])Image:Granite lavanda blue.jpg|Lavanda Blue (Brazil) Engineers have traditionally used polished granite surfaces to establish a Plane (mathematics) of reference, since they are relatively impervious and inflexible. Sandblasted concrete with a heavy Aggregate (composite) content has an appearance similar to rough granite, and is often used as a substitute when use of real granite is impractical. A most unusual use of granite was in the construction of the rails for the Haytor Granite Tramway, Devon, England, in 1820. Curling stones are traditionally fashioned of Ailsa Craig granite. The first stones were made in the 1750s, the original source being Ailsa Craig in Scotland. Because of the particular rarity of the granite, the best stones can cost as much as $1500 (USD). Between 60–70 percent of the stones used today are made from Ailsa Craig granite, although the island is now a wildlife reserve and is no longer used for quarrying.

Rock climbing in ChileGranite is one of the rocks most prized by climbers, for its steepness, soundness, crack systems, and friction. Well-known venues for granite climbing include Yosemite Valley, the The Bugaboos, the Mont Blanc massif (and peaks such as the Aiguille du Dru, the Aiguille du Midi and the Grandes Jorasses), the Bregaglia Range, Corsica, parts of the Karakoram, the Torres_del_Paine, Baffin Island, the Cornwall and the Cairngorms.

Granite Rock climbing is so popular that many of the artificial rock Climbing wall found in gyms and theme parks are made to look and feel like granite. Most, however, are made from manufactured materials, given the fact that granite is generally too heavy for portable rock climbing walls, as well as the buildings in which stationary walls are located.

See also

References

External links

, valley of the Merced River. The quarrying consists of splitting up the blocks

Granite (International Phonetic Alphabet: ) is a common and widely occurring type of Intrusion (geology), felsic, igneous rock rock (geology). Granites are usually medium to coarsely crystalline, occasionally with some individual crystals larger than the groundmass forming a rock known as Porphyry (geology). Granites can be pink to dark gray or even black, depending on their chemistry and mineralogy. Outcrops of granite tend to form tor (geography), and rounded massifs. Granites sometimes occur in circular depression (geology)s surrounded by a range of hills, formed by the Metamorphism#Contact_(Thermal)_metamorphism or hornfels.

Granite is nearly always massive (lacking internal structures), hard and tough, and therefore it has gained widespread use as a construction stone. The average density of granite is 2.75 gcm−3 with a range of 1.74 gcm−3 to 2.80 gcm−3. The word granite comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a crystalline rock.

Mineralogy Granite is classified according to the QAPF diagram for coarse grained pluton (granitoids) and is named according to the percentage of quartz, alkali feldspar (orthoclase, sanidine, or microcline) and plagioclase feldspar on the A-Q-P half of the diagram. Granite-like rocks which are normative mineralogy may have a feldspathoid such as nepheline, and are classified on the A-F-P half of the diagram.

True granite according to modern petrology convention contains both plagioclase and alkali feldspars. When a granitoid is devoid or nearly devoid of plagioclase the rock is referred to as alkali granite. When a granitoid contains

Occurrence is a granite monolith in British ColumbiaGranite is currently known only on Earth where it forms a major part of continental crust. Granite often occurs as relatively small, less than 100 km² stock masses (stocks) and in batholiths that are often associated with orogeny mountain ranges. Small dike (geology) of granitic composition called aplites are often associated with the margins of granitic Intrusion (geology)s. In some locations very coarse-grained pegmatite masses occur with granite.

Granite has been intruded into the Crust (geology) of the Earth during all Geologic ages, although much of it is of Precambrian age. Granitic rock is widely distributed throughout the continental crust of the Earth and is the most abundant basement rock that underlies the relatively thin sedimentary rock veneer of the continents.

Despite being fairly common throughout the world, the areas with the most commercial granite quarry are located in Finland, Norway and Sweden (Bohuslän), Spain (mostly Galicia (Iberia) and Extremadura), Brazil, India and several countries in southern Africa, namely Angola, Namibia, Zimbabwe and South Africa.

Origin Granite is an igneous rock and is formed from magma. Granitic magma has many potential origins but it must intrude other rocks. Most granite intrusions are emplaced at depth within the crust, usually greater than 1.5 kilometres and up to 50 km depth within thick continental crust. The origin of granite is contentious and has led to varied schemes of classification. Classification schemes are regional; there is a French scheme, a British scheme and an American scheme. This confusion arises because the classification schemes define granite by different means. Generally the 'alphabet-soup' classification is used because it classifies based on genesis or origin of the magma.

Geochemical origins Granitoids are a ubiquitous component of the crust. They have crystallized from magmas that have compositions at or near a eutectic point (or a temperature minimum on a cotectic curve). Magmas will evolve to the eutectic because of igneous differentiation, or because they represent low degrees of partial melting. Fractional crystallization (geology) serves to reduce a melt in iron, magnesium, titanium, calcium and sodium, and enrich the melt in potassium and silicon - alkali feldspar (rich in potassium) and quartz (SiO2), are two of the defining constituents of granite.

This process operates regardless of the origin of the parental magma to the granite, and regardless of its chemistry. However, the composition and origin of the magma which differentiates into granite, leaves certain geochemical and mineralogical evidence as to what the granite's parental rock was. The final mineralogy, texture and chemical composition of a granite is often distinctive as to its origin. For instance, a granite which is formed from melted sediments may have more alkali feldspar, whereas a granite derived from melted basalt may be richer in plagioclase feldspar. It is on this basis that the modern "alphabet" classification schemes are based.

Alphabet Soup Classification The 'alphabet soup' scheme of Chappell & White was proposed initially to divide granites into I-type granite (or igneous protolith) granite and S-type or sedimentary protolith graniteChappell, B.W. and White, A.J.R., 2001. Two contrasting granite types: 25 years later. Australian Journal of Earth Sciences v.48, p.489-499.. Both of these types of granite are formed by melting of high grade metamorphic rocks, either other granite or intrusive mafic rocks, or buried sediment, respectively.

M-type or Mantle (geology) derived granite was proposed later, to cover those granites which were clearly sourced from crystallised mafic magmas, generally sourced from the mantle. These are rare, because it is difficult to turn basalt into granite via fractional crystallisation.

A-type or anorogenic granites are formed above volcanic "hot spot" activity and have peculiar mineralogy and geochemistry. These granites are formed by melting of the lower crust under conditions that are usually extremely dry. The granite of Yellowstone caldera is an example of an A-type granite.

Granitization An old, and largely discounted theory, granitization states that granite is formed in place by extreme metamorphism. The production of granite by metamorphic heat is difficult, but is observed to occur in certain amphibolite and granulite terrains. In-situ granitisation or melting by metamorphism is difficult to recognise except where leucosome and melanosome (geology) textures are present in gneisses. Once a metamorphic rock is melted it is no longer a metamorphic rock and is a magma, so these rocks are seen as a transitional between the two, but are not technically granite as they do not actually intrude into other rocks. In all cases, melting of solid rock requires high temperature, and also water or other volatiles which act as a catalyst by lowering the solidus (chemistry) temperature of the rock.

Ascent and emplacement The ascent and emplacement of large volumes of granite within the upper continental crust is a source of much debate amongst geologists. There is a lack of field evidence for any proposed mechanisms, so hypotheses are predominantly based upon experimental data.There are two major hypotheses for the ascent of magma through the crust: Of these two mechanisms, Stokes diapir was favoured for many years in the absence of a reasonable alternative. The basic idea is that magma will rise through the crust as a single mass through buoyancy. As it rises it heats the Country rock (geology), causing them to behave as a power law fluid and thus flow around the pluton allowing it to pass rapidly and without major heat loss (Weinberg, 1994). This is entirely feasible in the warm, Ductility lower crust where rocks are easily deformed, but runs into problems in the upper crust which is far colder and more brittle. Rocks there do not deform so easily: for magma to rise as a pluton it would expend far too much energy in heating wall rocks, thus cooling and solidifying before reaching higher levels within the crust.Nowadays fracture propagation is the mechanism preferred by many geologists as it largely eliminates the major problems of moving a huge mass of magma through cold brittle crust. Magma rises instead in small channels along self-propagating Dike (geology) which form along new or pre-existing Fault (geology) systems and networks of active shear zones (Clemens, 1997). As these narrow conduits open, the first magma to enter solidifies and provides a form of insulation for later magma.Granitic magma must make room for itself or be intruded into other rocks in order to form an intrusion, and several mechanisms have been proposed to explain how large batholiths have been emplaced:

Most geologists today accept that a combination of these phenomena can be used to explain granite intrusions, and that not all granites can be explained by one or another mechanism.

Natural Radiation Granite is a normal, geological, source of Particle radiation in the natural environment. Granite contains around 10 to 20 parts per million of uranium. By contrast, more mafic rocks such as tonalite, gabbro or diorite have 1 to 5 ppm uranium, and limestones and sedimentary rocks usually have equally low amounts.

Many large granite plutons are the sources for palaeochannel-hosted or roll front uranium ore deposits, where the uranium washes into the sediments from the granite uplands and associated, often highly radioactive, pegmatites.

In buildings constructed primarily from natural granite, it is possible to be exposed to approximately 200 Röntgen equivalent man per year. Lehigh University

Granite could be considered a potential natural radiological hazard as, for instance, villages located over granite may be susceptible to higher doses of radiation than other communites. Radiation and Life Cellars and basements sunk into soils formed over or from particularly uraniferous granites can become a trap for radon gas, which is heavier than air.

However, in the majority of cases, although granite is a significant source of natural radiation as compared to other rocks it is not often an acute health threat or significant risk factor. Various resources from national geological survey organisations are accessible online to assist in assessing the risk factors in granite country and design rules relating, in particular, to preventing accumulation of radon gas in enclosed basements and dwellings.

Uses Antiquity The Red Pyramid of Ancient Egypt (c.26th century BC), named for the light crimson hue of its exposed granite surfaces, is the third largest of Egyptian pyramids. Menkaure's Pyramid, likely dating to the same era, was constructed of limestone and granite blocks. The Great Pyramid of Giza (c.26th century BC) contains a huge granite sarcophagus fashioned of "Red Aswan Granite." The mostly ruined Black Pyramid dating from the reign of Amenemhat III once had a polished granite pyramidion or capstone, now on display in the main hall of the Egyptian Museum in Cairo (see Dahshur). Other uses in Ancient Egypt, include columns, door lintels, sills, jambs, and wall and floor veneer. How the Egyptians worked the solid granite is still a matter of debate. Dr. Patrick Hunt has postulated that the Egyptians used Emery (mineral) shown to have higher Hardenability on the Mohs scale of mineral hardness.

Many large Hindu temples in southern India, particularly those built by the 11th century king Rajaraja Chola I, were made of granite. There is a large amount of granite in these structures. They are comparable to the Great Pyramid of Giza.

Modern Granite has been extensively used as a dimension stone and as flooring tiles in public and commercial buildings and monuments. With increasing amounts of acid rain in parts of the world, granite has begun to supplant marble as a monument material, since it is much more durable. Polished granite is also a popular choice for kitchen countertops due to its high durability and aesthetic qualities. Image:Granite azul noce.jpg])Image:Granite giallo.jpg|Santa Cecelia(Brazil)Image:Granite_gran_violet.jpg])Image:Granite lavanda blue.jpg|Lavanda Blue (Brazil) Engineers have traditionally used polished granite surfaces to establish a Plane (mathematics) of reference, since they are relatively impervious and inflexible. Sandblasted concrete with a heavy Aggregate (composite) content has an appearance similar to rough granite, and is often used as a substitute when use of real granite is impractical. A most unusual use of granite was in the construction of the rails for the Haytor Granite Tramway, Devon, England, in 1820. Curling stones are traditionally fashioned of Ailsa Craig granite. The first stones were made in the 1750s, the original source being Ailsa Craig in Scotland. Because of the particular rarity of the granite, the best stones can cost as much as $1500 (USD). Between 60–70 percent of the stones used today are made from Ailsa Craig granite, although the island is now a wildlife reserve and is no longer used for quarrying.

Rock climbing in ChileGranite is one of the rocks most prized by climbers, for its steepness, soundness, crack systems, and friction. Well-known venues for granite climbing include Yosemite Valley, the The Bugaboos, the Mont Blanc massif (and peaks such as the Aiguille du Dru, the Aiguille du Midi and the Grandes Jorasses), the Bregaglia Range, Corsica, parts of the Karakoram, the Torres_del_Paine, Baffin Island, the Cornwall and the Cairngorms.

Granite Rock climbing is so popular that many of the artificial rock Climbing wall found in gyms and theme parks are made to look and feel like granite. Most, however, are made from manufactured materials, given the fact that granite is generally too heavy for portable rock climbing walls, as well as the buildings in which stationary walls are located.

See also

References

External links



 

Granite



 
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