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A rock is any naturally occurring solid mass or aggregate of
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure, that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

mineral
s or
mineraloid A mineraloid is a naturally occurring mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorph ...
matter. It is categorized by the minerals included, its
chemical composition{{Unreferenced, date=December 2017 Chemical composition refers to identity and nine number of the chemical elements that make up any particular compound. Composition of a substance The chemical is the an are the composition of a pure substance corr ...
and the way in which it is formed. Rocks form the Earth's outer solid layer, the crust, and most of its interior, except for the liquid
outer core Earth's outer core is a fluid layer about thick and composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. Its outer boundary lies beneath Earth's surface. The transition between the inner core and out ...
and pockets of
magma 300px, Hawaii. Lava is the extrusive">Hawaii (island)">Hawaii. Lava is the extrusive equivalent of magma. Magma (from Ancient Greek μάγμα (''mágma'') meaning "thick unguent") is the molten or semi-molten natural material from which al ...
in the
asthenosphere The asthenosphere ( grc, ἀσθενός 'asthenos''meaning "without strength", and thus "weak", and 'sphaira''meaning "sphere") is the highly viscous, mechanically weak, and ductile region of the upper mantle of Earth. It lies below the lithosph ...
. Rocks are usually grouped into three main groups:
igneous rock Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lav ...
s,
sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at the Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to ...
s and
metamorphic rock#REDIRECT Metamorphic rock#REDIRECT Metamorphic rock {{Redirect category shell, 1= {{R from other capitalisation ...
{{Redirect category shell, 1= {{R from other capitalisation ...
s. Igneous rocks are formed when
magma 300px, Hawaii. Lava is the extrusive">Hawaii (island)">Hawaii. Lava is the extrusive equivalent of magma. Magma (from Ancient Greek μάγμα (''mágma'') meaning "thick unguent") is the molten or semi-molten natural material from which al ...
cools in the Earth's crust, or
lava of pāhoehoe lava, Hawaii, United States , Iceland in 1984 Lava is molten Rock (geology), rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon. Magma is generated by the internal heat of the pla ...
cools on the ground surface or the seabed. Sedimentary rocks are formed by
diagenesis Diagenesis () is the process that describes physical and chemical changes in sediments first caused by water-rock interactions, microbial activity and compaction after their deposition. The increase of pressure and temperature only starts to play ...
or
lithification Lithification (from the Ancient Greek word ''lithos'' meaning 'rock' and the Latin-derived suffix ''-ific'') is the process in which sediments compact under pressure, expel connate fluids, and gradually become solid rock. Essentially, lithification ...
of
sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and ...
s, which in turn are formed by the
weathering Weathering is the breaking down of rocks, soils, and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), ...
, transport, and deposition of existing rocks. Metamorphic rocks are formed when existing rocks are subjected to such large pressures and temperatures that they are transformed—something that occurs, for example, when
continental plates upright=1.35, Diagram of the internal layering of Earth showing the lithosphere above the asthenosphere (not to scale) Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is a ...
collide. The scientific study of rocks is called
petrology A volcanic sand grain seen under the microscope, with plane-polarized light in the upper picture, and cross polarized light in the lower picture. Scale box is 0.25 mm. Petrology (from the grc, πέτρος, translit=pétros, lit=rock and grc, label= ...
, which is an essential component of
geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over t ...
.


Classification

Rocks are composed primarily of grains of minerals, which are
crystalline solids A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosco ...
formed from a
chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) composed of atoms from more than one element held together by chemical bonds. A molecule consisting of atoms of only one element is therefor ...
arranged in an orderly manner. The
aggregate Aggregate or aggregates may refer to: Computing and mathematics * collection of objects that are bound together by a root entity, otherwise known as an aggregate root. The aggregate root guarantees the consistency of changes being made within the ...
minerals forming the rock are held together by
chemical bond A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds or throug ...
s. Some rocks also contain
mineraloid A mineraloid is a naturally occurring mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorph ...
s, which are rigid, mineral-like substances, such as
volcanic glass Volcanic glass is the amorphous (uncrystallized) product of rapidly cooling magma. Like all types of glass, it is a state of matter intermediate between the close-packed, highly ordered array of a crystal and the highly disordered array of gas. Vol ...
, that lacks crystalline structure. The types and abundance of minerals in a rock are determined by the manner in which it was formed. Most rocks contain
silicate minerals Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide) SiO2 is usually cons ...
, compounds that include silicon oxide tetrahedra in their
crystal lattice A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosco ...
, and account for about one-third of all known mineral species and about 95% of the
earth's crust 350px, Plates in the crust of Earth Earth's crust is a thin shell on the outside of Earth, accounting for less than 1% of Earth's volume. It is the top component of the lithosphere, a division of Earth's layers that includes the crust and the upper ...
. The proportion of
silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

silica
in rocks and minerals is a major factor in determining their names and properties. Rocks are classified according to characteristics such as mineral and chemical composition, permeability,
texture Texture may refer to: Science and technology * Surface texture, the texture means smoothness, roughness, or bumpiness of the surface of an object * Texture (roads), road surface characteristics with waves shorter than road roughness * Texture (co ...
of the constituent particles, and
particle size Particle size is a notion introduced for comparing dimensions of solid particles (flecks), liquid particles (droplets), or gaseous particles (bubbles). The notion of particle size applies to colloidal particles, particles in ecology, particles pre ...
. These physical properties are the result of the processes that formed the rocks. Over the course of time, rocks can transform from one type into another, as described by a geological model called the
rock cycle The rock cycle is a basic concept in geology that describes transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous. Each rock type is altered when it is forced out of its equilibrium conditions. ...

rock cycle
. This transformation produces three general classes of rock:
igneous Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lav ...
,
sedimentary Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at the Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to ...
and
metamorphic#REDIRECT Metamorphic rock#REDIRECT Metamorphic rock#REDIRECT Metamorphic rock {{Redirect category shell, 1= {{R from other capitalisation ... {{Redirect category shell, 1= {{R from other capitalisation ...
{{Redirect category shell, 1= {{R f ...
. Those three classes are subdivided into many groups. There are, however, no hard-and-fast boundaries between allied rocks. By increase or decrease in the proportions of their minerals, they pass through gradations from one to the other; the distinctive structures of one kind of rock may thus be traced gradually merging into those of another. Hence the definitions adopted in rock names simply correspond to selected points in a continuously graduated series.


Igneous rock

Igneous rock (derived from the
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman Republic, it became the dominant language ...
word ''igneus,'' meaning ''of fire,'' from ''ignis'' meaning ''fire)'' is formed through the cooling and
solidification Freezing is a phase transition where a liquid turns into a solid when its temperature is lowered below its freezing point. In accordance with the internationally established definition, freezing means the solidification phase change of a liquid or ...
of
magma 300px, Hawaii. Lava is the extrusive">Hawaii (island)">Hawaii. Lava is the extrusive equivalent of magma. Magma (from Ancient Greek μάγμα (''mágma'') meaning "thick unguent") is the molten or semi-molten natural material from which al ...
or
lava of pāhoehoe lava, Hawaii, United States , Iceland in 1984 Lava is molten Rock (geology), rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a moon. Magma is generated by the internal heat of the pla ...
. This magma may be derived from partial melts of pre-existing rocks in either a
planet A planet is an astronomical body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and – according to the International Astronomical Union but not ...
's
mantle Mantle may refer to: *Mantle (geology), a layer in the interior of a planet ** The Earth's mantle *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox vesture worn by monasti ...
or crust. Typically, the melting of rocks is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Igneous rocks are divided into two main categories: *
Plutonic , an igneous ''intrusion'' exposed when the surrounding softer rock eroded away Intrusive rock is formed when magma penetrates existing rock, crystallizes, and solidifies underground to form ''intrusions'', such as batholiths, dikes, sills, lacco ...
or intrusive rocks result when magma cools and
crystallizes Crystallization or crystallisation is the process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some of the ways by which crystals form are precipitating from a solution, freezing, ...

crystallizes
slowly within the
Earth's crust 350px, Plates in the crust of Earth Earth's crust is a thin shell on the outside of Earth, accounting for less than 1% of Earth's volume. It is the top component of the lithosphere, a division of Earth's layers that includes the crust and the upper ...
. A common example of this type is
granite Granite () is a coarse-grained igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies underground. It is common in the E ...

granite
. * Volcanic or
extrusive A volcanic rock from Italy with a relatively large six-sided phenocryst (diameter about 1 mm) surrounded by a fine-grained groundmass, as seen in thin section under a petrographic microscope Extrusive rock refers to the mode of igneous vo ...
rocks result from magma reaching the surface either as lava or ''fragmental ejecta'', forming minerals such as
pumice Kutkhiny Baty, a pumice rock formation outcrop located 4 km from the source of the Ozernaya River (Lake Kurile), near the southern tip of the Kamchatka Peninsula, Russia.">Kamchatka Peninsula">Ozernaya River (Lake Kurile), near the southern ti ...

pumice
or
basalt Basalt (, ) is a fine-grained extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (''mafic '' lava) exposed at or very near the surface of a rocky planet or a moon. More than 90% of all volc ...
. The chemical abundance and the rate of cooling of magma typically forms a sequence known as
Bowen's reaction series Within the field of geology, Bowen's reaction series is the work of the petrologist Norman L. Bowen, who summarized, based on experiments and observations of natural rocks, the sequence of crystallization of common silicate minera ...

Bowen's reaction series
. Most major igneous rocks are found along this scale. About 65% of the Earth's crust by volume consists of igneous rocks, making it the most plentiful category. Of these, 66% are basalt and
gabbro Gabbro Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is ...
, 16% are granite, and 17%
granodiorite Photomicrograph of thin section of granodiorite from Slovakia (in crossed polarised light) Granodiorite () is a phaneritic-textured Intrusive rock, intrusive igneous rock similar to granite, but containing more plagioclase feldspar ...
and
diorite upright=1.4, Diorite classification on QAPF diagram Diorite () is an intrusive igneous rock composed principally of the silicate minerals plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene. The chemical composition ...
. Only 0.6% are
syenite leucocratic variety of nepheline syenite from Sweden">nepheline.html" style="text-decoration: none;"class="mw-redirect" title="leucocratic variety of nepheline">leucocratic variety of nepheline syenite from Sweden (särnaite) Syenite i ...
and 0.3% are
ultramafic Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed of ...
. The
oceanic crust#REDIRECT Oceanic crust#REDIRECT Oceanic crust {{R from other capitalisation ...
{{R from other capitalisation ...
is 99% basalt, which is an igneous rock of
mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...
composition. Granite and similar rocks, known as granitoids, dominate the
continental crust 350px, The thickness of Earth's crust (km) Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. Thi ...
.


Sedimentary rock

Sedimentary rocks are formed at the earth's surface by the accumulation and cementation of fragments of earlier rocks, minerals, and organisms or as chemical precipitates and organic growths in water (
sedimentation Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these for ...
). This process causes
clastic of a clast (sand grain), derived from a basalt scoria. Vesicles (air bubbles) can be seen throughout the clast. Plane light above, cross-polarized light below. Scale box is 0.25 mm. Clastic rocks are composed of fragments, or clasts, of pre-exi ...
sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and ...
s (pieces of rock) or organic particles (
detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts communit ...
) to settle and accumulate, or for minerals to chemically
precipitate Precipitation is the process of conversion of a chemical substance into a solid from a solution by converting the substance into an insoluble form or a super-saturated solution. When the reaction occurs in a liquid solution, the solid formed is ...
(
evaporite evaporated from the Dead Sea, Israel Evaporite () is the term for a water-soluble mineral sediment that results from concentration and crystallization by evaporation from an aqueous solution.Jackson, Julia A., 1997, Glossary of Geology 4th editi ...
) from a
solution Making a NaCl)_in_water.html" style="text-decoration: none;"class="mw-redirect" title="Salt">table salt (sodium chloride">NaCl) in water">Salt">table salt (sodium chloride">NaCl) in water. The salt is the solute and the water the solve ...
. The particulate matter then undergoes compaction and cementation at moderate temperatures and pressures (
diagenesis Diagenesis () is the process that describes physical and chemical changes in sediments first caused by water-rock interactions, microbial activity and compaction after their deposition. The increase of pressure and temperature only starts to play ...
). Before being deposited, sediments are formed by
weathering Weathering is the breaking down of rocks, soils, and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms. Weathering occurs ''in situ'' (on site, with little or no movement), ...
of earlier rocks by
erosion In earth science, erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location. Erosion is distinct from ...

erosion
in a source area and then transported to the place of deposition by
water Water is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vita ...
,
wind Wind is the flow of gases on a large scale. On the surface of the Earth, wind consists of the bulk movement of air. Winds are commonly classified by their spatial scale, their speed, the types of forces that cause them, the regions in which they ...
,
ice Ice is water frozen into a solid state. Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaque bluish-white color. In the Solar System, ice is abundant and occur ...
,
mass movement A mass movement denotes a political party or movement which is supported by large segments of a population. Political movements that typically advocate the creation of a mass movement include the ideologies of communism, fascism, and liberalism. B ...
or
glacier A glacier ( or ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. Glaciers slowly deform and flow under stres ...
s (agents of
denudation , Brazil: Cabo Frio Island and Itaúna Body. In geology, denudation involves the processes that cause the wearing away of the Earth's surface by moving water, by ice, by wind, and by waves, leading to a reduction in elevation and in relief of lan ...
). About 7.9% of the crust by volume is composed of sedimentary rocks, with 82% of those being shales, while the remainder consists of limestone (6%), sandstone and
arkose Arkose () is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose. Quartz is commonly the dominant mi ...
s (12%). Sedimentary rocks often contain
fossil A fossil (from Classical Latin: , literally "obtained by digging") is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or ...
s. Sedimentary rocks form under the influence of gravity and typically are deposited in horizontal or near horizontal layers or
strata (Argentina). , Canada. These are Middle Cambrian marine sediments. This formation covers over half of Nova Scotia and is recorded as being 8,800 m (29,000 ft) thick in some areas. In geology and related fields, a stratum (plural: strata) is a l ...
, and may be referred to as stratified rocks.


Metamorphic rock

Metamorphic rocks are formed by subjecting any rock type—sedimentary rock, igneous rock or another older metamorphic rock—to different
temperature Temperature is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy, present in all matter, which is the source of the occurrence of heat, a flow of energy, when a body is in contact with another that is ...
and
pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and ev ...
conditions than those in which the original rock was formed. This process is called
metamorphism upright=1.35, Schematic representation of a chlorite;_ep_=_epidote.html" style="text-decoration: none;"class="mw-redirect" title="actinolite">metamorphic reaction. Abbreviations of minerals: act = actinolite; chl = Chlorite group">chlorite; ep ...
, meaning to "change in form". The result is a profound change in physical properties and chemistry of the stone. The original rock, known as the
protolith A protolith (from Ancient Greek (), first and , stone) is the original, unmetamorphosed rock from which a given metamorphic rock is formed . For example, the protolith of a slate is a shale or mudstone. Metamorphic rocks can be derived from any ...
, transforms into other mineral types or other forms of the same minerals, by recrystallization. The temperatures and pressures required for this process are always higher than those found at the Earth's surface: temperatures greater than 150 to 200 °C and pressures of 1500 bars. Metamorphic rocks compose 27.4% of the crust by volume. The three major classes of metamorphic rock are based upon the formation mechanism. An intrusion of magma that heats the surrounding rock causes contact metamorphism—a temperature-dominated transformation. Pressure metamorphism occurs when sediments are buried deep under the ground; pressure is dominant, and temperature plays a smaller role. This is termed burial metamorphism, and it can result in rocks such as
jade Jade is an ornamental mineral, mostly known for its green varieties, though it appears naturally in other colors as well, notably yellow and white. Jade can refer to either of two different silicate minerals: nephrite (a silicate of calcium and ...
. Where both heat and pressure play a role, the mechanism is termed regional metamorphism. This is typically found in mountain-building regions. Depending on the structure, metamorphic rocks are divided into two general categories. Those that possess a texture are referred to as foliated; the remainders are termed non-foliated. The name of the rock is then determined based on the types of minerals present.
Schist Schist specimen showing the characteristic "scaly" schistose texture, caused by platy micas Schist (pronounced ) is a medium-grade metamorphic rock formed from mudstone or shale. Schist has medium to large, flat, sheet-like grains in a preferred o ...
s are foliated rocks that are primarily composed of lamellar minerals such as
mica Mica is a group of sheet silicate minerals, not to be confused with Micah. Mica or MICA may also refer to: Companies * Mica DIY, a UK Retailer Co-operative, Symbol group Acronyms * Mahone Islands Conservation Association * Ministry of Informa ...
s. A
gneiss Gneiss () is a common and widely distributed type of metamorphic rock. Gneiss is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Orthogneiss is gneiss derived from i ...

gneiss
has visible bands of differing
lightness In colorimetry and color theory, lightness, also known as value or tone, is a representation of a color's brightness. It is one of the color appearance parameters of any color appearance model. Various color models have an explicit term for th ...
, with a common example being the granite gneiss. Other varieties of foliated rock include
slate Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock.Ess ...
s,
phyllite polarised_light).html" style="text-decoration: none;"class="mw-redirect" title="thin section">Photomicrograph of polarised_light)">thin_section">Photomicrograph_of_thin_section_of_phyllite_(in_cross_Polarization_(waves)">polarised_light) Phylli ...
s, and
mylonite Mylonite is a fine-grained, compact metamorphic rock produced by dynamic recrystallization of the constituent minerals resulting in a reduction of the grain size of the rock. Mylonites can have many different mineralogical compositions; it is a clas ...
. Familiar examples of non-foliated metamorphic rocks include
marble Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated, although there are exceptions. In geology, the term ''marble'' refers to metamorphosed limestone, b ...
,
soapstone Soapstone (also known as steatite or soaprock) is a talc-schist, which is a type of metamorphic rock. It is composed largely of the magnesium rich mineral talc. It is produced by dynamothermal metamorphism and metasomatism, which occur in the zone ...
, and
serpentine Serpentine may refer to: Music * ''Serpentine'' (album), a 2002 goth metal album by Flowing Tears * "Serpentine" (song), a 2011 country song by Tiffany * ''Serpentines'' (Ingrid Laubrock album), a 2016 album * A 2010 alternative metal song by Dist ...
. This branch contains
quartzite Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tecton ...
—a metamorphosed form of
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones make up about 20 to 25 percent of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) be ...
—and
hornfelsA sample of banded hornfels, formed by contact metamorphism of sandstones and shales by a granite">shale.html" style="text-decoration: none;"class="mw-redirect" title="sandstones and shale">sandstones and shales by a granite intrusion Ho ...
.


Human use

The use of rock has had a huge impact on the cultural and technological development of the human race. Rock has been used by humans and other
hominids The Hominidae (), whose members are known as great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: ''Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the eastern and ...
for at least 2.5 million years.
Lithic technology In archaeology, lithic technology includes a broad array of techniques used to produce usable tools from various types of stone. The earliest stone tools were recovered from modern Ethiopia and were dated to between two-million and three-million y ...
marks some of the oldest and continuously used technologies. The
mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. These deposits form a mineralized commodity that is of economic interest to the min ...
of rock for its
metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ...
content has been one of the most important factors of human advancement, and has progressed at different rates in different places, in part because of the kind of metals available from the rock of a region.


Mining

Mining is the extraction of valuable
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure, that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

mineral
s or other
geological Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over t ...
materials from the earth, from an ore body,
vein Veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart. In contrast to ...
or seam. The term also includes the removal of soil. Materials recovered by mining include
base metals A base metal is a common and inexpensive metal, as opposed to a precious metal such as gold or silver. A long-time goal of alchemists was the transmutation of a base (low grade) metal into a precious metal. In numismatics, coins often derived their ...
,
precious metals Precious metals are rare, naturally occurring metallic chemical elements of high economic value. Chemically, the precious metals tend to be less reactive than most elements (see noble metal). They are usually ductile and have a high lustre. H ...
,
iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is by mass the most common element on Earth, right in front of o ...

iron
,
uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...
,
coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements; chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dead p ...

coal
,
diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. At room temperature and pressure, another solid form of carbon known as graphite is the chemically stable form of carbon, but di ...

diamond
s,
limestone Limestone is a common type of carbonate sedimentary rock. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (). Limestone forms when these minerals precipitate out of water con ...
,
oil shale Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced, called shale oil. Shale oil is a substitute for conventional crude oi ...
,
rock salt Halite ( or ), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride (Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, p ...
,
potash Potash () includes various mined and manufactured salts that contain potassium in water-soluble form.
,
construction aggregate quarry. rock or aggregate, for use in concrete, called "blue metal" in Australia. , Croatia. Construction aggregate, or simply aggregate (composite), aggregate, is a broad category of coarse- to medium-grained particulate material used in con ...
and
dimension stone Dimension stone is natural stone or rock that has been selected and finished (e.g., trimmed, cut, drilled, ground, or other) to specific sizes or shapes. Color, texture and pattern, and surface finish of the stone are also normal requirements. An ...
. Mining is required to obtain any material that cannot be grown through
agricultural Agriculture is the science, art and practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peo ...
processes, or created
artificially Artificiality (the state of being artificial or man-made) is the state of being the product of intentional human manufacture, rather than occurring naturally through processes not involving or requiring human activity. Connotations Artificiality of ...
in a
laboratory A laboratory (, ; colloquially lab) is a facility that provides controlled conditions in which scientific or technological research, experiments, and measurement may be performed. Laboratory services are provided in a variety of settings: phy ...
or
factory A factory, manufacturing plant or a production plant is an industrial site, often a complex consisting of several buildings filled with machinery, where workers manufacture items or operate machines which process each item into another. They are ...

factory
. Mining in a wider sense comprises extraction of any
resource A resource is a source or supply from which a benefit is produced and that has some utility. Resources can broadly be classified upon their availability — they are classified into renewable and non-renewable resources. They can also be classifie ...

resource
(e.g.
petroleum Petroleum (), also known as crude oil and oil, is a naturally occurring, yellowish-black liquid found in geological formations beneath the Earth's surface. It is commonly refined into various types of fuels. Components of petroleum are separate ...
,
natural gas Natural gas (also called fossil gas; sometimes just gas) is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carb ...
,
salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in its natural form as a crystalline mineral is known as rock salt or halite. Salt is present in vast quantities ...
or even
water Water is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vita ...
) from the earth. Mining of rock and metals has been done since
prehistoric Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the invention of writing systems. The use of symbols, marks, and images appears very e ...
times. Modern mining processes involve
prospecting Prospecting is the first stage of the geological analysis (followed by exploration) of a territory. It is the search for minerals, fossils, precious metals, or mineral specimens. It is also known as fossicking. Traditionally prospecting relie ...
for mineral deposits, analysis of the profit potential of a proposed mine, extraction of the desired materials, and finally reclamation of the land to prepare it for other uses once mining ceases. Mining processes may create negative impacts on the environment both during the mining operations and for years after mining has ceased. These potential impacts have led to most of the world's nations adopting regulations to manage negative effects of mining operations.


See also

*
Building material Building material is material used for construction. Many naturally occurring substances, such as clay, rocks, sand, and wood, even twigs and leaves, have been used to construct buildings. Apart from naturally occurring materials, many man-made ...
*
History of Earth The history of Earth concerns the development of planet Earth from its formation to the present day. Nearly all branches of natural science have contributed to understanding of the main events of Earth's past, characterized by constant geologica ...
*
Geologic time scale The geologic time scale (GTS) is a system of chronological dating that classifies geological strata (stratigraphy) in time. It is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships of events i ...
*
Geomorphology incised into shale at the foot of the North Caineville Plateau, Utah, within the pass carved by the Fremont River and known as the Blue Gate. GK Gilbert studied the landscapes of this area in great detail, forming the observational foundation for ...
*
Boulder This balancing boulder, "Balanced Rock", stands in Colorado Springs, Colorado, United States.">Colorado Springs, CO">Colorado Springs, Colorado, United States. , Québec File:Kämmenkivi stone in Pisa, Kuopio, Finland.jpg, ''Kämmenkivi'' stone on ...

Boulder
*
List of rock types The following is a list of rock types recognized by geologists. There is no agreed number of specific types of rocks. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can descri ...
* Oldest rock *
Stone industry Stone industry refers to the part of the primary sector of the economy, similar to the mining industry, but concerned with excavations of stones, in particular granite, marble, slate and sandstone. Other products of the industry include crushed sto ...


References


External links

* * * {{DEFAULTSORT:Rock (Geology) Petrology
Materials A category for both scientific and industrial classifications of matter and materials. Goods (economics) Matter {{CatAutoTOC ...