Granite (pronounced /ˈɡrænɨt/) is a common and widely occurring type of intrusive An intrusion is liquid rock that forms under the surface of the earth. Magma from under the surface slowly moves its way up from deep within the earth and moves into any cracks or spaces it can find, sometimes pushing existing country rock out of the way, a process that can take millions of years or more to form. As the rock slowly cools into a, felsic Felsic is a term used in geology to refer to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. The term combines the words "feldspar" and "silica". Felsic minerals are usually light in color and have specific gravities less than 3. Common, igneous Igneous rock is one of the three main rock types (the others being sedimentary and metamorphic rock). Igneous rock is formed by magma or lava (molten rock) cooling and becoming solid. Igneous rock may form with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. This rock In geology, rock is a naturally occurring solid aggregate of minerals and/or mineraloids. Granites usually have a medium to coarse grained texture. Occasionally some individual crystals (phenocrysts A phenocryst is a relatively large and usually conspicuous crystal distinctly larger than the grains of the rock groundmass of a porphyritic igneous rock. Phenocrysts often have euhedral forms either due to early growth within a magma or by post-emplacement recrystallization) are larger than the groundmass The matrix or groundmass of rock is the fine-grained mass of material in which larger grains or crystals are embedded in which case the texture is known as porphyritic Rock microstructure includes the texture of a rock and the small scale rock structures. The words "texture" and "microstructure" are interchangeable, with the latter preferred in modern geological literature. However, texture is still acceptable because it is a useful means of identifying the origin of rocks, how they formed,. A granitic rock with a porphyritic texture is sometimes known as a porphyry Porphyry is a variety of igneous rock consisting of large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass. The larger crystals are called phenocrysts. In its non-geologic, traditional use, the term "porphyry" refers to the purple-red form of this stone, valued for its appearance. Granites can be pink to gray in color, depending on their chemistry and mineralogy. By definition, granite has a color index (i.e. the percentage of the rock made up of dark minerals) of less than 25%. Outcrops An outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth.[citation needed] of granite tend to form tors A tor is a rock outcrop formed by weathering, usually found on or near the summit of a hill. In the South West of England, where the term originated, it is also a word used for the hills themselves – particularly the high points of Dartmoor in Devon and Bodmin Moor in Cornwall, and rounded massifs In geology, a massif is a section of a planet's crust that is demarcated by faults or flexures. In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole. The term is also used to refer to a group of mountains formed by such a structure. In mountaineering and climbing literature, a massif is. Granites sometimes occur in circular depressions Depression in geology is a landform sunken or depressed below the surrounding area. Depressions may be formed by various mechanisms, and may be referred to by a variety of technical terms such as: surrounded by a range of hills, formed by the metamorphic aureole or hornfels Hornfels is the group designation for a series of contact metamorphic rocks that have been baked and indurated by the heat of intrusive igneous masses and have been rendered massive, hard, splintery, and in some cases exceedingly tough and durable.

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 The density of a material is defined as its mass per unit volume. The symbol of density is ρ . In some countries (for instance, in the United States), density is also defined as its weight per unit volume of granite is located between 2.65[1] and 2.75 g/cm3, its compressive strength usually lies above 200 MPa and its viscosity Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. For example, high-viscosity felsic magma will create a tall, steep stratovolcano, because it cannot flow far before it cools, while low-viscosity mafic lava will create a wide, shallow-sloped shield volcano. All real fluids have some at standard temperature and pressure is 3-6 • 1019 Pa·s.[2]

The word granite comes from the Latin Latin or sometimes Roman is an Italic language originally spoken in Latium and Ancient Rome. Although often considered a dead language, in view of the fact that it has no native, fluent speakers, Latin continues to be taught in schools and has been, and currently is, used in the process of new word production in modern languages from many granum, a grain, in reference to the coarse-grained structure of such a crystalline A crystal or crystalline solid is a solid material, whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is crystallography. The process of crystal formation via mechanisms of crystal growth is called rock.

Granitoid is used as a descriptive field term for general, light colored, coarse-grained igneous rocks for which a more specific name requires petrographic Petrography is a branch of petrology that focuses on detailed descriptions of rocks. Someone who studies petrography is called a petrographer. The mineral content and the textural relationships within the rock are described in detail. Petrographic descriptions start with the field notes at the outcrop and include megascopic description of hand examination.[3]

Contents

Mineralogy

Orbicular granite near the town of Caldera, northern Chile Chile (traditional English pronunciation /ˈtʃɪli/, also pronounced /ˈtʃiːleɪ/ ), officially the Republic of Chile (Spanish: República de Chile [reˈpuβlika ðe ˈtʃile] ( listen)), is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders

Granite is classified according to the QAPF diagram A QAPF diagram is a double triangle diagram which is used to classify igneous rocks based on mineralogic composition. The acronym, QAPF, stands for "Quartz, Alkali feldspar, Plagioclase, Feldspathoid ". These are the mineral groups used for classification in QAPF diagram. Q, A, P and F percentages are normalized (recalculated so that for coarse grained plutonic rocks A pluton in geology is an intrusive igneous rock body that crystallized from magma slowly cooling below the surface of the Earth. Plutons include batholiths, dikes, sills, laccoliths, lopoliths, and other igneous bodies. In practice, "pluton" usually refers to a distinctive mass of igneous rock, typically kilometers in dimension, without and is named according to the percentage of quartz Quartz is the second most abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2, alkali feldspar Feldspars crystallize from magma in both intrusive and extrusive igneous rocks, as veins, and are also present in many types of metamorphic rock. Rock formed almost entirely of calcic plagioclase feldspar is known as anorthosite. Feldspars are also found in many types of sedimentary rock (orthoclase Orthoclase is a common constituent of most granites and other felsic igneous rocks and often forms huge crystals and masses in pegmatite, sanidine Sanidine is the high temperature form of potassium feldspar (Si,Al)4O8. Sanidine most typically occurs in felsic volcanic rocks such as obsidian, rhyolite and trachyte. Sanidine crystallizes in the monoclinic crystal system. Orthoclase is a monoclinic polymorph stable at lower temperatures. At yet lower temperatures, microcline, a triclinic, or microcline Microcline is an important igneous rock-forming tectosilicate mineral. It is a potassium-rich alkali feldspar. Microcline typically contains minor amounts of sodium. It is common in granite and pegmatites. Microcline forms during slow cooling of orthoclase; it is more stable at lower temperatures than orthoclase. Sanidine is a polymorph of alkali) and plagioclase Plagioclase is an important series of tectosilicate minerals within the feldspar family. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a solid solution series, more properly known as the plagioclase feldspar series . This was first shown by the German mineralogist Johann Friedrich Christian feldspar on the A-Q-P half of the diagram. True granite according to modern petrologic Petrology is the branch of geology that studies rocks, and the conditions in which rocks form 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 <10% orthoclase it is called tonalite Tonalite is an igneous, plutonic rock, of felsic composition, with phaneritic texture. Feldspar is present as plagioclase (typically oligoclase or andesine) with 10% or less alkali feldspar. Quartz is present as more than 20% of the rock. Amphiboles and pyroxenes are common accessory minerals; pyroxene The pyroxenes are a group of important rock-forming silicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems. Pyroxenes have the general formula XY2O6 (where X represents calcium, sodium, iron+2 and and amphibole Amphibole defines an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain SiO4 tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Amphiboles crystallize into two crystal systems, monoclinic and orthorhombic. In chemical composition and are common in tonalite. A granite containing both muscovite and biotite micas The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic with a tendency towards pseudo-hexagonal crystals and are similar in chemical composition. The highly perfect cleavage, which is the most prominent characteristic of mica, is explained by the hexagonal sheet- is called a binary or two-mica granite. Two-mica granites are typically high in potassium Potassium is the chemical element with the symbol K (Latin: kalium, from Arabic: القَلْيَه‎ al-qalyah "plant ashes" cf. Alkali from the same root, more commonly known in Modern Standard Arabic as بوتاسيوم ‹bwtasywm›), atomic number 19, and atomic mass 39.0983. Potassium was first isolated from potash. Elemental and low in plagioclase, and are usually S-type granites or A-type granites. The volcanic A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, ash and gases to escape from below the surface equivalent of plutonic A pluton in geology is an intrusive igneous rock body that crystallized from magma slowly cooling below the surface of the Earth. Plutons include batholiths, dikes, sills, laccoliths, lopoliths, and other igneous bodies. In practice, "pluton" usually refers to a distinctive mass of igneous rock, typically kilometers in dimension, without granite is rhyolite This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade. Granite has poor primary permeability but strong secondary permeability.

Chemical composition

A worldwide average of the chemical composition of granite, by weight percent:[4]

The Stawamus Chief is a granite monolith A monolith is a geological feature such as a mountain, consisting of a single massive stone or rock, or a single piece of rock placed as, or within, a monument. Erosion usually exposes the geological formations, which are most often made of very hard and solid metamorphic or igneous rock in British Columbia

Based on 2485 analyses

Occurrence

Granite is currently known only on Earth where it forms a major part of continental crust The continental crust is the layer of igneous, sedimentary, and metamorphic rocks which form the continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called sial due to more felsic, or granitic, bulk composition, which lies in contrast to the oceanic crust, called sima due to its. Granite often occurs as relatively small, less than 100 km² stock masses (stocks) and in batholiths A batholith is a large emplacement of igneous intrusive (also called plutonic) rock that forms from cooled magma deep in the earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock-types, such as granite, quartz monzonite, or diorite (see also granite dome) that are often associated with orogenic Orogeny refers to forces and events leading to a severe structural deformation of the earth's crust due to the engagement of tectonic plates. Response to such engagement results in the formation of long tracts of highly deformed rock called orogens or orogenic belts. The word "orogeny" comes from the Greek , and it is the primary mountain ranges. Small dikes of granitic composition called aplites are often associated with the margins of granitic intrusions. In some locations very coarse-grained pegmatite masses occur with granite.

Granite has been intruded into the crust of the Earth during all geologic periods, 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 veneer of the continents.

Origin

Close-up of granite exposed in Chennai, India.

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 and include French, British, and American systems.

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 crystallisation 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.

Close-up of granite from Yosemite National Park, valley of the Merced River

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 mineral 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.

Chappell & White classification system

The letter-based Chappell & White classification system was proposed initially to divide granites into I-type granite (or igneous protolith) granite and S-type or sedimentary protolith granite.[5] 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 derived granite was proposed later, to cover those granites which were clearly sourced from crystallized 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 rhyolites of the Yellowstone caldera are examples of volcanic equivalents of A-type granite.[6][7]

Granitization

An old, and largely discounted theory, granitization states that granite is formed in place by extreme metasomatism by fluids bringing in elements e.g. potassium and removing others e.g. calcium to transform the metamorphic rock into a granite. This was supposed to occur across a migrating front. 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 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 temperature of the rock.

Ascent and emplacement

Roche Rock, Cornwall The Cheesewring, a granite tor on the southern edge of Bodmin Moor, Cornwall

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 wall rocks, 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.[8] This is entirely feasible in the warm, ductile 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 dykes which form along new or pre-existing fault systems and networks of active shear zones (Clemens, 1998).[9] 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 entirely by one or another mechanism.

Natural radiation

Granite is a natural source of radiation, like most natural stones. However, some granites have been reported to have higher radioactivity thereby raising some concerns about their safety.

Some granites contain 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. 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 communities.[10] Cellars and basements sunk into soils over granite can become a trap for radon gas, which is formed by the decay of uranium.[11] Radon can also be introduced into houses by wells drilled into granite.[12] Radon gas poses significant health concerns, and is the #2 cause of lung cancer in the US behind smoking.[12]

There is some concern that materials sold as granite countertops or as building material may be hazardous to health. One expert, Dr. Dan Steck of St. Johns University, has stated[13] that approximately 5% of all granites will be of concern, with the caveat that only a tiny percentage of the tens of thousands of granite slabs have been actually tested. Various resources from national geological survey organizations 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.

A study of granite countertops was done (initiated and paid for by the Marble Institute of America) in November 2008 by National Health and Engineering Inc of USA, and found that all of the 39 full size granite slabs that were measured for the study showed radiation levels well below the European Union safety standards (section 4.1.1.1 of the National Health and Engineering study) and radon emission levels well below the average outdoor radon concentrations in the US.[14]

Other researchers and organizations do not agree with the Marble Institute's stated position on granite safety, including AARST (American Association of Radon Scientists and Technicians) and the CRCPD (Conference of Radiation Control Program Directors, an organization of state radiation protection officials).[citation needed] Both organizations have committees currently setting maximum allowed levels of radiation/radon as well as protocols for measuring radiation/radon from granite countertops. The European Union regulations will likely serve as the basis for new EPA based regulations for granite building materials in the U.S.[citation needed]

Uses

Antiquity

Life-size elephant and other creatures carved in granite; Mahabalipuram, India.

The Red Pyramid of 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.2580 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.[15] How the Egyptians worked the solid granite is still a matter of debate. Dr. Patrick Hunt[16] has postulated that the Egyptians used emery shown to have higher hardness on the Mohs scale.

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.[17]

Modern

Building

Quarrying granite for the Mormon Temple, Utah Territory, in Little Cottonwood Canyon Polished red granite tombstone Granite was used for cobblestones on the St. Louis riverfront and for the piers of the Eads Bridge (background).

Granite has been extensively used as a dimension stone and as flooring tiles in public and commercial buildings and monuments. Because of its abundance, granite was commonly used to build foundations for homes in New England. The Granite Railway, America's first railroad, was built to haul granite from the quarries in Quincy, Massachusetts, to the Neponset River in the 1820s. 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. In building and for countertops, the term "granite" is often applied to all igneous rocks with large crystals, and not specifically to those with a granitic composition.

Other uses

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 US$1,500. 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.[18]

In some areas granite is used for gravestones and memorials. Granite is a hard stone and requires skill to carve by hand. Modern methods of carving include using computer-controlled rotary bits and sandblasting over a rubber stencil. Leaving the letters, numbers and emblems exposed on the stone, the blaster can create virtually any kind of artwork or epitaph.

Engineering

Engineers have traditionally used polished granite surfaces to establish a plane of reference, since they are relatively impervious and inflexible. Sandblasted concrete with a heavy aggregate 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.

Rock climbing

The granite peaks of the Torres del Paine in the Chilean Patagonia

Granite 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, the Bugaboos, the Mont Blanc massif (and peaks such as the Aiguille du Dru, the Mountains of Mourne, the Aiguille du Midi and the Grandes Jorasses), the Bregaglia, Corsica, parts of the Karakoram (especially the Trango Towers), the Fitzroy Massif, Patagonia, Baffin Island, the Cornish coast and the Cairngorms.

Granite rock climbing is so popular that many of the artificial rock climbing walls found in gyms and theme parks are made to look and feel like granite.

Half Dome, Yosemite, a classic granite dome and popular rock climb

See also

References

  1. ^ "Basic Rock Mechanics". Webpages.sdsmt.edu. http://webpages.sdsmt.edu/~lstetler/merlot/rock_mechanics.htm. Retrieved 2010-05-09.
  2. ^ Kumagai, Naoichi; Sadao Sasajima, Hidebumi Ito (15 February 1978). "Long-term Creep of Rocks: Results with Large Specimens Obtained in about 20 Years and Those with Small Specimens in about 3 Years". Journal of the Society of Materials Science (Japan) (Japan Energy Society) 27 (293): 157–161. http://translate.google.com/translate?hl=en&sl=ja&u=http://ci.nii.ac.jp/naid/110002299397/&sa=X&oi=translate&resnum=4&ct=result&prev=/search%3Fq%3DIto%2BHidebumi%26hl%3Den. Retrieved 2008-06-16.
  3. ^ "Granitoids - Granite and the Related Rocks Granodiorite, Diorite and Tonalite". Geology.about.com. 2010-02-06. http://geology.about.com/od/more_igrocks/a/granitoids.htm. Retrieved 2010-05-09.
  4. ^ Harvey Blatt and Robert J. Tracy (1997). Petrology (2nd ed.). New York: Freeman. p. 66. ISBN 0716724383.
  5. ^ Chappell, 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.
  6. ^ Boroughs, S., Wolff, J., Bonnichsen, B., Godchaux, M., and Larson, P., 2005, Large-volume, low-δ18O rhyolites of the central Snake River Plain, Idaho, USA: Geology 33: 821–824.
  7. ^ C.D. Frost, M. McCurry, R. Christiansen, K. Putirka and M. Kuntz, Extrusive A-type magmatism of the Yellowstone hot spot track 15th Goldschmidt Conference Field Trip AC-4. Field Trip Guide, University of Wyoming (2005) 76 pp., plus an appended map.
  8. ^ Weinberg, R. F., and Podladchikov, Y., Diapiric ascent of magmas through power-law crust and mantle, 1994, J. Geophys. Res., 99, 9543-9559
  9. ^ Clemens, John (1998). "Observations on the origins and ascent mechanisms of granitic magmas". Journal of the Geological Society of London 155 (Part 5): 843–51. doi:10.1144/gsjgs.155.5.0843.
  10. ^ "Radiation and Life". World Nuclear Association. July 2002. http://world-nuclear.org/education/ral.htm. Retrieved 2010-02-04.
  11. ^ "Decay series of Uranium". http://www.world-nuclear.org/images/info/decayseries.gif. Retrieved 2008-10-19.
  12. ^ a b "Radon and Cancer: Questions and Answers". National Cancer Institute. http://www.cancer.gov/cancerTopics/factsheet/Risk/radon. Retrieved 2008-10-19.
  13. ^ Steck, Daniel J. (2009). "Pre- and Post-Market Measurements of Gamma Radiation and Radon Emanation from a Large Sample of Decorative Granites". http://www.aarst.org/proceedings/2009/PRE-AND_POST-MARKET_MEASUREMENTS_OF_GAMMA_RADIATION_AND_RADON_EMANATION_FROM_A_LARGE_SAMPLE_OF_DECORATIVE_GRANITES.pdf.
  14. ^ http://www.marble-institute.com/industryresources/assessingexposureexecutivesummary.pdf Assessing Exposure to Radon and Radiation from Granite Countertops
  15. ^ James A. Harrell. "Decorative Stones in the Pre-Ottoman Islamic Buildings of Cairo, Egypt". http://www.eeescience.utoledo.edu/Faculty/Harrell/Egypt/Mosques/CAIRO_Rocks_1.htm. Retrieved 2008-01-06.
  16. ^ "Egyptian Genius: Stoneworking for Eternity". http://hebsed.home.comcast.net/hunt.htm. Retrieved 2008-01-06.
  17. ^ "The Lost Temples of India" (video). http://video.google.com/videoplay?docid=8931191297840928556&q=Lost+temples+India. Retrieved 2008-01-06.
  18. ^ "National Geographic News — Puffins Return to Scottish Island Famous for Curling Stones". News.nationalgeographic.com. http://news.nationalgeographic.com/news/2004/10/1027_041027_curling_stones.html. Retrieved 2009-07-30.

External links

Wikimedia Commons has media related to: Granite
Igneous rocks by composition
Type Ultramafic < 45% SiO2 Mafic < 52% SiO2 Intermediate 52–63% SiO2 Intermediate-Felsic 63–69% SiO2 Felsic >69 % SiO2

Volcanic rocks: Subvolcanic rocks: Plutonic rocks:

Komatiite Kimberlite, Lamproite Peridotite

Basalt Diabase (Dolerite) Gabbro

Andesite Diorite

Dacite Granodiorite

Rhyolite Aplite—Pegmatite Granite

Categories: Granitic rocks | Felsic rocks | Symbols of Wisconsin | Plutonic rocks | National symbols of Finland

 

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of being violently destroyed limestone fragments were strewn throughout the area along with ash and other signs of burning This season we found hundreds of fragments of pink and black granite again indicators of a violent destruction Only a few of the fragments contained hieroglyphs indicating that the granite objects likely came from statues and or stelae that were

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Michael Jackson's 3.5 tonne Black Granite Statue set World Record ...

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Wed, 28 Jul 2010 12:47:00 GM

"We want to do something different in that, so we built a Michael Jackson statue in single black . granite. which weighs about 3.5 tonnes and we want to send the statue to Michael Jackson foundation. So we entered in India Book of Records ...

Google Blogs Search: Granite,
Thu Jul 29 22:58:43 2010
'Granite' Answers
How can I make one slab of granite a little darker to match another?
Q. I just installed a granite counter, one slab is slightly lighter than the others, someone said just seal the lighter, or put oil on it and seal. When it gets wet, it almost matches, but if the others get wet it also goes darker, any suggestions?
Asked by stymiegold - Sun Nov 25 22:40:27 2007 - - 3 Answers - 0 Comments

A. YOu can't. Granite is a natual material. They aren't suppose to match. That's what makes it a beautiful product to use.
Answered by Lynn - Sun Nov 25 22:50:16 2007

Yahoo Answers Search: Granite,
Mon Jul 26 12:38:34 2010
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