HOME

TheInfoList




A crystal or crystalline solid is a
solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied ...

solid
material whose constituents (such as
atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atom ...

atom
s,
molecule A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an electrically Electricity is the set of physical phenomena associated with the presence and motion I ...

molecule
s, or
ion An ion () is an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ...
s) are arranged in a highly ordered microscopic structure, forming a
crystal lattice In geometry and crystallography, a Bravais lattice, named after , is an infinite array of discrete points generated by a set of Translation operator (quantum mechanics)#Discrete Translational Symmetry, discrete translation operations described in th ...
that extends in all directions. In addition, macroscopic
single crystal A single-crystal, or monocrystalline, solid Solid is one of the four fundamental states of matter (the others being liquid, gas and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic e ...
s are usually identifiable by their geometrical shape, consisting of flat
faces The face is the front of an animal's head that features three of the head's Sense, sense organs, the eyes, nose, and mouth, and through which animals express many of their Emotion, emotions. The face is crucial for human Personal identity, ident ...
with specific, characteristic orientations. The scientific study of crystals and crystal formation is known as
crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' "cold drop, frozen drop" ...

crystallography
. The process of crystal formation via mechanisms of
crystal growth A crystal 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 addit ...
is called
crystallization Crystallization or crystallisation is the process by which a solid Solid is one of the four fundamental states of matter (the others being liquid, gas and plasma). The molecules in a solid are closely packed together and contain the ...

crystallization
or
solidification Freezing is a phase transition In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, ...
. The word ''crystal'' derives from the
Ancient Greek Ancient Greek includes the forms of the Greek language Greek ( el, label=Modern Greek Modern Greek (, , or , ''Kiní Neoellinikí Glóssa''), generally referred to by speakers simply as Greek (, ), refers collectively to the diale ...
word (), meaning both "
ice Ice is water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known forms of , eve ...

ice
" and "
rock crystal Quartz is a hard, crystalline mineral composed of silicon and oxygen atoms. The atoms are linked in a continuous framework of SiO4 silicon-oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, g ...
", from (), "icy cold, frost". Examples of large crystals include
snowflake A snowflake is a single ice crystal Ice is water Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the mai ...

snowflake
s,
diamond Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. At Standard conditions for temperature and pressure, room temperature and pressure, another solid form of ...

diamond
s, and
table salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of Salt (chemistry), salts; salt in the form of a natural crystallinity, crystalline mineral is known as rock salt or halite. ...
. Most inorganic solids are not crystals but
polycrystal A crystallite is a small or even microscopic crystal A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In phys ...
s, i.e. many microscopic crystals fused together into a single solid. Examples of polycrystals include most
metals A metal (from Ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts Electrical resistivity and conductivity, e ...
, rocks,
ceramics A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant Corrosion is a Erosion, natural process that converts a refined metal into a more chemically stable form such as oxide, hydroxide, carbonate or sulfide. It ...

ceramics
, and
ice Ice is water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known forms of , eve ...

ice
. A third category of solids is
amorphous solid In condensed matter physics Condensed matter physics is the field of that deals with the macroscopic and microscopic physical properties of , especially the and which arise from forces between s. More generally, the subject deals with " ...
s, where the atoms have no periodic structure whatsoever. Examples of amorphous solids include
glass Glass is a non- crystalline, often transparency and translucency, transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by ...

glass
,
wax Waxes are a diverse class of organic compound In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, prope ...
, and many
plastic Plastics are a wide range of syntheticA synthetic is an artificial material produced by organic chemistry, organic chemical synthesis. Synthetic may also refer to: In the sense of both "combination" and "artificial" * Synthetic chemical or s ...

plastic
s. Despite the name, lead crystal, crystal glass, and related products are ''not'' crystals, but rather types of glass, i.e. amorphous solids. Crystals are often used in
pseudoscientific Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual but are incompatible with the scientific method. Pseudoscience is often characterized by contradictory, exaggerated or falsifiability, un ...
practices such as crystal therapy, and, along with
gemstone A gemstone (also called a fine gem, jewel, precious stone, or semi-precious stone) is a piece of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chem ...

gemstone
s, are sometimes associated with spellwork in
Wicca Wicca () is a modern Pagan religion. Scholars of religion categorise it as both a new religious movement A new religious movement (NRM), also known as a new religion or an alternative spirituality, is a religious or spirituality, spiritual ...
n beliefs and related religious movements.


Crystal structure (microscopic)

The scientific definition of a "crystal" is based on the microscopic arrangement of atoms inside it, called the
crystal structure In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' "co ...

crystal structure
. A crystal is a solid where the atoms form a periodic arrangement. (
Quasicrystal A quasiperiodic crystal 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 dire ...

Quasicrystal
s are an exception, see
below Below may refer to: *Earth *Ground (disambiguation) *Soil *Floor *Bottom (disambiguation) *Less than *Temperatures below freezing *Hell or underworld People with the surname *Fred Below (1926–1988), American blues drummer *Fritz von Below (1853 ...
). Not all solids are crystals. For example, when liquid water starts freezing, the phase change begins with small ice crystals that grow until they fuse, forming a ''
polycrystalline A crystallite is a small or even microscopic crystal 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 ...
'' structure. In the final block of ice, each of the small crystals (called "
crystallite A crystallite is a small or even microscopic crystal A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In phys ...

crystallite
s" or "grains") is a true crystal with a periodic arrangement of atoms, but the whole polycrystal does ''not'' have a periodic arrangement of atoms, because the periodic pattern is broken at the
grain boundaries A grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are 2D crystallographic defect, defects in the crystal structure, and tend to decrease the electrical conductivity, electrical ...
. Most macroscopic
inorganic In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they under ...
solids are polycrystalline, including almost all
metal A metal (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is appro ...

metal
s,
ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant Corrosion is a Erosion, natural process that converts a refined metal into a more chemically stable form such as oxide, hydroxide, carbonate or sulfide. ...

ceramic
s,
ice Ice is water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known forms of , eve ...

ice
,
rocks In 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 rock (geology), rocks of which it is composed, and the proc ...
, etc. Solids that are neither crystalline nor polycrystalline, such as
glass Glass is a non- crystalline, often transparency and translucency, transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by ...

glass
, are called ''
amorphous solid In condensed matter physics Condensed matter physics is the field of that deals with the macroscopic and microscopic physical properties of , especially the and which arise from forces between s. More generally, the subject deals with " ...
s'', also called
glass Glass is a non- crystalline, often transparency and translucency, transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by ...

glass
y, vitreous, or noncrystalline. These have no periodic order, even microscopically. There are distinct differences between crystalline solids and amorphous solids: most notably, the process of forming a glass does not release the
latent heat of fusion The enthalpy of fusion of a substance, also known as (latent) heat of fusion is the change in its enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. ...
, but forming a crystal does. A crystal structure (an arrangement of atoms in a crystal) is characterized by its ''unit cell'', a small imaginary box containing one or more atoms in a specific spatial arrangement. The unit cells are
stacked ''Stacked'' is an American television Situation comedy, sitcom that aired on Fox Broadcasting Company, Fox from April 13, 2005 to January 11, 2006. Premise ''Stacked'' was described as the opposite of ''Cheers'', instead of a smart person in a " ...
in three-dimensional space to form the crystal. The
symmetry of a crystal
symmetry of a crystal
is constrained by the requirement that the unit cells stack perfectly with no gaps. There are 219 possible crystal symmetries, called crystallographic space groups. These are grouped into 7
crystal system In crystallography, the terms crystal system, crystal family, and lattice system each refer to one of several classes of space groups, Bravais lattice, lattices, point groups, or crystals. Informally, two crystals are in the same crystal system i ...
s, such as
cubic crystal system In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' " ...
(where the crystals may form cubes or rectangular boxes, such as
halite Halite (), commonly known as rock salt, is a type of salt Salt is a mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition a ...
shown at right) or
hexagonal crystal system In crystallography, the hexagonal crystal family is one of the six crystal family, crystal families, which includes two crystal systems (hexagonal and trigonal) and two lattice systems (hexagonal and rhombohedral). While commonly confused, the tri ...
(where the crystals may form hexagons, such as ordinary water ice).


Crystal faces and shapes

Crystals are commonly recognized by their shape, consisting of flat faces with sharp angles. These shape characteristics are not ''necessary'' for a crystal—a crystal is scientifically defined by its microscopic atomic arrangement, not its macroscopic shape—but the characteristic macroscopic shape is often present and easy to see.
Euhedral Euhedral crystals (also known as idiomorphic or automorphic crystals) are those that are well-formed, with sharp, easily recognised face (geometry) , faces. The opposite is anhedral (also known as ''Xenomorph (geology), xenomorphic'' or ''allot ...
crystals are those with obvious, well-formed flat faces. Anhedral crystals do not, usually because the crystal is one grain in a polycrystalline solid. The flat faces (also called
facet Facets () are flat faces on geometric shapes. The organization of naturally occurring facets was key to early developments in crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline so ...
s) of a
euhedral Euhedral crystals (also known as idiomorphic or automorphic crystals) are those that are well-formed, with sharp, easily recognised face (geometry) , faces. The opposite is anhedral (also known as ''Xenomorph (geology), xenomorphic'' or ''allot ...
crystal are oriented in a specific way relative to the underlying
atomic arrangement of the crystal
atomic arrangement of the crystal
: they are
planes Plane or planes may refer to: * Airplane An airplane or aeroplane (informally plane) is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, Propeller (aircraft), propeller, or rocket engine. Airplanes come in a va ...
of relatively low
Miller index Miller indices form a notation system in crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek la ...
. This occurs because some surface orientations are more stable than others (lower
surface energy Surface free energy or interfacial free energy or surface energy quantifies the disruption of intermolecular bonds that occurs when a surface is created. In the of s, surfaces must be intrinsically less than the bulk of a material (the molecules ...
). As a crystal grows, new atoms attach easily to the rougher and less stable parts of the surface, but less easily to the flat, stable surfaces. Therefore, the flat surfaces tend to grow larger and smoother, until the whole crystal surface consists of these plane surfaces. (See diagram on right.) One of the oldest techniques in the science of
crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' "cold drop, frozen drop" ...

crystallography
consists of measuring the three-dimensional orientations of the faces of a crystal, and using them to infer the underlying
crystal symmetry In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek words ''crystallon'' "cold drop, frozen ...
. A crystal's habit is its visible external shape. This is determined by the
crystal structure In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' "co ...

crystal structure
(which restricts the possible facet orientations), the specific crystal chemistry and bonding (which may favor some facet types over others), and the conditions under which the crystal formed.


Occurrence in nature


Rocks

By volume and weight, the largest concentrations of crystals in the Earth are part of its solid
bedrock Bedrock in geology Geology (from the γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is a branch of concerned with both the liquid and , the of which it is composed, and the processes by which they cha ...

bedrock
. Crystals found in rocks typically range in size from a fraction of a millimetre to several centimetres across, although exceptionally large crystals are occasionally found. , the world's largest known naturally occurring crystal is a crystal of
beryl Beryl ( ) is a mineral In 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 rock (geology), rocks of which i ...

beryl
from Malakialina,
Madagascar Madagascar (; mg, Madagasikara), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), and previously known as the Malagasy Republic The Malagasy Republic ( mg, Repoblika Mal ...

Madagascar
, long and in diameter, and weighing . Some crystals have formed by
magmatic 300px, Hawaii Hawaii ( ; haw, Hawaii or ) is a U.S. state in the Western United States, in the Pacific Ocean about 2,000 miles (3,200 km) from the U.S. mainland. It is the only state outside North America, the only island state, and ...
and
metamorphic Metamorphic rocks arise from the transformation of existing rock Rock most often refers to: * Rock (geology) A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the mineral ...
processes, giving origin to large masses of crystalline
rock Rock most often refers to: * Rock (geology) A rock is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition and the way in w ...
. The vast majority of
igneous rocks Igneous rock (derived from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the p ...

igneous rocks
are formed from molten magma and the degree of crystallization depends primarily on the conditions under which they solidified. Such rocks as
granite Granite () is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive 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 cool ...

granite
, which have cooled very slowly and under great pressures, have completely crystallized; but many kinds of
lava Lava is magma Magma () is the molten or semi-molten natural material from which all s are formed. Magma is found beneath the surface of the , and evidence of has also been discovered on other and some s. Besides molten rock, magma may al ...

lava
were poured out at the surface and cooled very rapidly, and in this latter group a small amount of amorphous or
glass Glass is a non- crystalline, often transparency and translucency, transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by ...

glass
y matter is common. Other crystalline rocks, the metamorphic rocks such as
marble Marble is a metamorphic rock , a type of metamorphic rock Metamorphic rocks arise from the transformation of existing rock (geology), rock to new types of rock, in a process called metamorphism upright=1.35, Schematic representation of ...

marble
s, mica-schists and
quartzite Quartzite is a hard, non-Foliation (geology), 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 usu ...

quartzite
s, are recrystallized. This means that they were at first fragmental rocks like
limestone Limestone is a common type of carbonate In chemistry, a carbonate is a salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of Salt (chemistry), salts; salt in its na ...

limestone
,
shale Shale is a fine-grained, clastic Clastic rocks are composed of fragments, or clasts, of pre-existing minerals In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defi ...

shale
and
sandstone Sandstone is a clastic sedimentary rock of a clast (sand grain), derived from a basalt Basalt (, ) is a fine-grained extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron ('' mafic ' ...

sandstone
and have never been in a
molten Melting, or fusion, is a physical process that results in the phase transition In chemistry, thermodynamics, and many other related fields, phase transitions (or phase changes) are the Physical process, physical processes of transition betw ...
condition nor entirely in solution, but the high temperature and pressure conditions of
metamorphism Metamorphism is the change 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 nat ...
have acted on them by erasing their original structures and inducing recrystallization in the solid state. Other rock crystals have formed out of precipitation from fluids, commonly water, to form druses or
quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, ...

quartz
veins.
Evaporite An evaporite () is a water-solubility, soluble sedimentation, sedimentary mineral deposition (geology), deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposit ...
s such as
halite Halite (), commonly known as rock salt, is a type of salt Salt is a mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition a ...
,
gypsum Gypsum is a soft sulfate mineral The sulfate minerals are a class of mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with ...

gypsum
and some limestones have been deposited from aqueous solution, mostly owing to
evaporation Evaporation is a type of vaporization Vaporization (or vaporisation) of an element or compound is a phase transition from the liquid phase to vapor. There are two types of vaporization: evaporation and boiling. Evaporation is a surface phe ...

evaporation
in arid climates.


Ice

Water-based
ice Ice is water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known forms of , eve ...

ice
in the form of
snow Snow comprises individual ice Ice is water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). ...

snow
,
sea ice Sea ice arises as seawater Seawater, or salt water, is water Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, whic ...

sea ice
, and
glacier A glacier (; ) is a persistent body of dense ice Ice is into a state. Depending on the presence of such as particles of soil or bubbles of air, it can appear transparent or a more or less bluish-white color. In the , ice is abunda ...

glacier
s are common crystalline/polycrystalline structures on Earth and other planets. A single
snowflake A snowflake is a single ice crystal Ice is water Water is an Inorganic compound, inorganic, Transparency and translucency, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the mai ...

snowflake
is a single crystal or a collection of crystals, while an
ice cube O'Shea Jackson Sr. (born June 15, 1969), known professionally as Ice Cube, is an American rapper, actor, and filmmaker. His lyrics on N.W.A N.W.A (an abbreviation for Niggaz Wit Attitudes) was an American hip hop Hip hop or hip-hop ...

ice cube
is a
polycrystal A crystallite is a small or even microscopic crystal A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In phys ...
.


Organigenic crystals

Many living
organisms In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, physiological me ...

organisms
are able to produce crystals, for example
calcite Calcite is a carbonate mineral Carbonate minerals are those mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid E ...

calcite
and
aragonite Aragonite is a , one of the three most common naturally occurring of , (the other forms being the s and ). It is formed by biological and physical processes, including precipitation from marine and freshwater environments. The of aragonite d ...

aragonite
in the case of most
mollusc Mollusca is the second-largest phylum In biology, a phylum (; plural The plural (sometimes list of glossing abbreviations, abbreviated ), in many languages, is one of the values of the grammatical number, grammatical category of number ...
s or
hydroxylapatite Hydroxyapatite, also called hydroxylapatite (HA), is a naturally occurring mineral form of calcium apatite with the Chemical formula, formula Ca5(PO4)3(OH), but it is usually written Ca10(PO4)6(OH)2 to denote that the Crystal structure, crysta ...
in the case of
vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellular A multicellular organism is an organism In biology, an organism () is any organic, life, living system that functions as an indiv ...
s.


Polymorphism and allotropy

The same group of atoms can often solidify in many different ways. Polymorphism is the ability of a solid to exist in more than one crystal form. For example, water
ice Ice is water Water (chemical formula H2O) is an , transparent, tasteless, odorless, and , which is the main constituent of 's and the s of all known living organisms (in which it acts as a ). It is vital for all known forms of , eve ...

ice
is ordinarily found in the hexagonal form Ice Ih, but can also exist as the cubic Ice Ic, the
rhombohedral In geometry, a rhombohedron (also called a rhombic hexahedron) is a three-dimensional figure with six faces which are rhombus, rhombi. It is a special case of a parallelepiped where all edges are the same length. It can be used to define the rhom ...

rhombohedral
ice II Ice II is a rhombohedral In geometry Geometry (from the grc, γεωμετρία; ' "earth", ' "measurement") is, with , one of the oldest branches of . It is concerned with properties of space that are related with distance, shape, siz ...
, and many other forms. The different polymorphs are usually called different '' phases''. In addition, the same atoms may be able to form noncrystalline phases. For example, water can also form
amorphous ice Amorphous ice (non-crystalline or "vitreous" ice) is an amorphous solid In condensed matter physics and materials science The interdisciplinary field of materials science, also commonly termed materials science and engineering, covers the ...
, while SiO2 can form both
fused silica Fused quartz, fused silica or quartz glass is a glass Glass is a non- crystalline, often transparency and translucency, transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window pa ...
(an amorphous glass) and
quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, ...

quartz
(a crystal). Likewise, if a substance can form crystals, it can also form polycrystals. For pure chemical elements, polymorphism is known as
allotropy Allotropy or allotropism () is the property of some chemical elements to exist in two or more different forms, in the same physical State of matter, state, known as allotropes of the elements. Allotropes are different structural modifications o ...
. For example,
diamond Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. At Standard conditions for temperature and pressure, room temperature and pressure, another solid form of ...

diamond
and
graphite Graphite (), archaically referred to as plumbago, is a Crystallinity, crystalline form of the element carbon with its atoms arranged in a Hexagonal crystal system, hexagonal structure. It occurs naturally in this form and is the most stable for ...

graphite
are two crystalline forms of
carbon Carbon (from la, carbo "coal") is a with the C and 6. It is lic and —making four s available to form s. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three occur naturally, ...

carbon
, while
amorphous carbonAmorphous carbon is free, reactive carbon that does not have any crystalline A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid, gas and plasma). The molecules ...
is a noncrystalline form. Polymorphs, despite having the same atoms, may have wildly different properties. For example, diamond is among the hardest substances known, while graphite is so soft that it is used as a lubricant. Polyamorphism is a similar phenomenon where the same atoms can exist in more than one
amorphous solid In condensed matter physics Condensed matter physics is the field of that deals with the macroscopic and microscopic physical properties of , especially the and which arise from forces between s. More generally, the subject deals with " ...
form.


Crystallization

Crystallization is the process of forming a crystalline structure from a fluid or from materials dissolved in a fluid. (More rarely, crystals may be deposited directly from gas; see
thin-film deposition A thin film is a layer of material ranging from fractions of a nanometer (monolayer) to several micrometre, micrometers in thickness. The controlled synthesis of materials as thin films (a process referred to as deposition) is a fundamental step i ...
and
epitaxy Epitaxy refers to a type of crystal growth or material deposition in which new crystalline layers are formed with one or more well-defined orientations with respect to the crystalline seed layer. The deposited crystalline film is called an epit ...
.) Crystallization is a complex and extensively-studied field, because depending on the conditions, a single fluid can solidify into many different possible forms. It can form a
single crystal A single-crystal, or monocrystalline, solid Solid is one of the four fundamental states of matter (the others being liquid, gas and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic e ...
, perhaps with various possible phases,
stoichiometries Stoichiometry is the calculation of reactants and Product (chemistry), products in chemical reactions in chemistry. Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equals the total mass of the ...
, impurities,
defects A defect is a physical, functional, or aesthetic attribute of a product or service that exhibits that the product or service failed to meet one of the desired specifications. Defect, defects or defected may also refer to: Examples * Angular defect ...
, and
habits A habit (or wont as a humorous and formal term) is a routine of that is repeated regularly and tends to occur .
. Or, it can form a
polycrystal A crystallite is a small or even microscopic crystal A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In phys ...
, with various possibilities for the size, arrangement, orientation, and phase of its grains. The final form of the solid is determined by the conditions under which the fluid is being solidified, such as the chemistry of the fluid, the
ambient pressure Ambient or Ambiance or Ambience may refer to: Music and sound * Ambience (sound recording)In filmmaking, ambience (also known as atmosphere, atmos, or background) consists of the sounds of a given location or space. It is the opposite of "silence" ...
, the
temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal energy refers to several distinct physical concept ...

temperature
, and the speed with which all these parameters are changing. Specific industrial techniques to produce large single crystals (called ''
boules ''Boules'' () is a collective name for a wide range of games similar to bowls Bowls, or lawn bowls, is a sport Sport pertains to any form of Competition, competitive physical activity or game that aims to use, maintain or improve physic ...
'') include the
Czochralski process The Czochralski method, also Czochralski technique or Czochralski process, is a method of crystal growth A crystal is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three ...

Czochralski process
and the
Bridgman techniqueBridgman is a surname, and may refer to: * David Bridgman, Australian architect * Elijah Coleman Bridgman (1801–1861), American missionary in China * Frederick Arthur Bridgman (1847-1928), American artist * George Bridgman (1865-1943), anatomis ...
. Other less exotic methods of crystallization may be used, depending on the physical properties of the substance, including
hydrothermal synthesis crystal grown by the hydrothermal method Hydrothermal synthesis includes the various techniques of crystallizing substances from high-temperature aqueous solution An aqueous solution is a solution Image:SaltInWaterSolutionLiquid.jpg, Making ...
, sublimation, or simply solvent-based crystallization. Large single crystals can be created by geological processes. For example,
selenite Selenite may refer to: Substances containing selenium *A selenium-containing anion or ionic compound with the SeO32− anion: **Selenite (ion), anion is a selenium oxoanion with the chemical formula SeO32− ***Selenous acid, the conjugate acid, wi ...
crystals in excess of 10
meter The metre ( Commonwealth spelling) or meter (American spelling Despite the various English dialects spoken from country to country and within different regions of the same country, there are only slight regional variations in English ...

meter
s are found in the
Cave of the Crystals Cave of the Crystals or Giant Crystal Cave () is a cave A cave or cavern is a natural void in the ground, specifically a space large enough for a human to enter. Caves often form by the weathering Weathering is the breaking down of rocks ...
in Naica, Mexico. For more details on geological crystal formation, see above. Crystals can also be formed by biological processes, see above. Conversely, some organisms have special techniques to ''prevent'' crystallization from occurring, such as
antifreeze protein Antifreeze proteins (AFPs) or ice structuring proteins (ISPs) refer to a class of polypeptides produced by certain animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological ...
s.


Defects, impurities, and twinning

An ''ideal'' crystal has every atom in a perfect, exactly repeating pattern. However, in reality, most crystalline materials have a variety of
crystallographic defect Crystallographic defects are interruptions of regular patterns in crystalline solids A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid, gas and plasma). Th ...
s, places where the crystal's pattern is interrupted. The types and structures of these defects may have a profound effect on the properties of the materials. A few examples of crystallographic defects include
vacancy defect Vacancy or No Vacancy may refer to: Economics * Vacancy (economics) A job, employment, work or occupation, is a person A person (plural people or persons) is a being that has certain capacities or attributes such as reason, morality, consc ...
s (an empty space where an atom should fit),
interstitial defect An interstitial defect is a type of point crystallographic defect where an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by havin ...
s (an extra atom squeezed in where it does not fit), and
dislocation In materials science The interdisciplinary Interdisciplinarity or interdisciplinary studies involves the combination of two or more academic discipline An academic discipline or academic field is a subdivision of knowledge that is Edu ...

dislocation
s (see figure at right). Dislocations are especially important in
materials science The interdisciplinary Interdisciplinarity or interdisciplinary studies involves the combination of two or more academic disciplines into one activity (e.g., a research project). It draws knowledge from several other fields like sociology, a ...
, because they help determine the mechanical strength of materials. Another common type of crystallographic defect is an
impurity Impurities are chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ...
, meaning that the "wrong" type of atom is present in a crystal. For example, a perfect crystal of
diamond Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. At Standard conditions for temperature and pressure, room temperature and pressure, another solid form of ...

diamond
would only contain
carbon Carbon (from la, carbo "coal") is a with the C and 6. It is lic and —making four s available to form s. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three occur naturally, ...

carbon
atoms, but a real crystal might perhaps contain a few
boron Boron is a chemical element In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behav ...

boron
atoms as well. These boron impurities change the
diamond's color
diamond's color
to slightly blue. Likewise, the only difference between
ruby A ruby is a pink-ish red to blood-red colored gemstone A gemstone (also called a fine gem, jewel, precious stone, or semi-precious stone) is a piece of mineral In geology and mineralogy, a mineral or mineral species is, broadly spea ...

ruby
and
sapphire Sapphire is a precious gemstone A gemstone (also called a fine gem, jewel, precious stone, or semi-precious stone) is a piece of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical c ...

sapphire
is the type of impurities present in a
corundum Corundum is a crystal A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance th ...

corundum
crystal. In
semiconductor A semiconductor material has an electrical conductivity Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric curre ...
s, a special type of impurity, called a
dopant A dopant, also called a doping agent, is a trace of impurity element that is introduced into a chemical material to alter its original electrical Electricity is the set of physical phenomena associated with the presence and motion Imag ...
, drastically changes the crystal's electrical properties.
Semiconductor device A device is an that relies on the properties of a material (primarily , , and , as well as s) for its function. Semiconductor devices have replaced s in most applications. They in the , rather than as free electrons across a (typically l ...
s, such as
transistor upright=1.4, gate Candi bentar, a typical Indonesian gate that is often found on the islands of Java">Indonesia.html" ;"title="Candi bentar, a typical Indonesia">Candi bentar, a typical Indonesian gate that is often found on the islands o ...

transistor
s, are made possible largely by putting different semiconductor dopants into different places, in specific patterns.
Twinning Twinning (making a twin of) may refer to: * In biology and agriculture, producing two offspring (i.e., twins) at a time, or having a tendency to do so; * Twin towns and sister cities, towns and cities involved in town twinning * Twinning institut ...
is a phenomenon somewhere between a crystallographic defect and a
grain boundary of a polycrystalline A crystallite is a small or even microscopic crystal 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, for ...
. Like a grain boundary, a twin boundary has different crystal orientations on its two sides. But unlike a grain boundary, the orientations are not random, but related in a specific, mirror-image way.
Mosaicity In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek words ''crystallon'' "cold drop, frozen d ...
is a spread of crystal plane orientations. A mosaic crystal consists of smaller crystalline units that are somewhat misaligned with respect to each other.


Chemical bonds

In general, solids can be held together by various types of
chemical bond A chemical bond is a lasting attraction between atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyda ...
s, such as
metallic bond Metallic bonding is a type of chemical bond A chemical bond is a lasting attraction between atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has m ...
s,
ionic bond Ionic bonding is a type of chemical bond A chemical bond is a lasting attraction between atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and t ...
s,
covalent bond A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they s ...
s, van der Waals bonds, and others. None of these are necessarily crystalline or non-crystalline. However, there are some general trends as follows.
Metal A metal (from Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is appro ...

Metal
s are almost always polycrystalline, though there are exceptions like
amorphous metal An amorphous metal (also known as metallic glass or glassy metal) is a solid metallic material, usually an alloy, with disordered atomic-scale structure. Most metals are crystalline in their solid state, which means they have a highly ordered arr ...
and single-crystal metals. The latter are grown synthetically. (A microscopically-small piece of metal may naturally form into a single crystal, but larger pieces generally do not.)
Ionic compound In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during ...
materials are usually crystalline or polycrystalline. In practice, large
salt Salt is a 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 fo ...
crystals can be created by solidification of a
molten Melting, or fusion, is a physical process that results in the phase transition In chemistry, thermodynamics, and many other related fields, phase transitions (or phase changes) are the Physical process, physical processes of transition betw ...
fluid, or by crystallization out of a solution.
Covalently bonded A covalent bond is a 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 Coulomb's law, electrostatic force of attraction bet ...
solids (sometimes called covalent network solids) are also very common, notable examples being
diamond Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. At Standard conditions for temperature and pressure, room temperature and pressure, another solid form of ...

diamond
and
quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tetrahedra, ...

quartz
. Weak
van der Waals force In molecular physics Molecular physics is the study of the physical properties of molecule File:Pentacene on Ni(111) STM.jpg, A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings ...
s also help hold together certain crystals, such as crystalline molecular solids, as well as the interlayer bonding in
graphite Graphite (), archaically referred to as plumbago, is a Crystallinity, crystalline form of the element carbon with its atoms arranged in a Hexagonal crystal system, hexagonal structure. It occurs naturally in this form and is the most stable for ...

graphite
.
Polymer A polymer (; Greek ''poly- Poly, from the Greek :wikt:πολύς, πολύς meaning "many" or "much", may refer to: Businesses * China Poly Group Corporation, a Chinese business group, and its subsidiaries: ** Poly Property, a Hong Kong inc ...

Polymer
materials generally will form crystalline regions, but the lengths of the molecules usually prevent complete crystallization—and sometimes polymers are completely amorphous.


Quasicrystals

A
quasicrystal A quasiperiodic crystal 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 dire ...

quasicrystal
consists of arrays of atoms that are ordered but not strictly periodic. They have many attributes in common with ordinary crystals, such as displaying a discrete pattern in
x-ray diffraction X-ray crystallography (XRC) is the experimental science determining the atomic and molecular structure of a crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a ...
, and the ability to form shapes with smooth, flat faces. Quasicrystals are most famous for their ability to show five-fold symmetry, which is impossible for an ordinary periodic crystal (see
crystallographic restriction theorem The crystallographic restriction theorem in its basic form was based on the observation that the rotational symmetries Rotational symmetry, also known as radial symmetry in biology, is the property a shape has when it looks the same after some ro ...
). The
International Union of Crystallography The International Union of Crystallography (IUCr) is an organisation devoted to the international promotion and coordination of the science of crystallography Crystallography is the experimental science of determining the arrangement of atoms in ...
has redefined the term "crystal" to include both ordinary periodic crystals and quasicrystals ("any solid having an essentially discrete
diffraction Diffraction refers to various phenomena that occur when a wave In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which r ...

diffraction
diagram"). Quasicrystals, first discovered in 1982, are quite rare in practice. Only about 100 solids are known to form quasicrystals, compared to about 400,000 periodic crystals known in 2004. The 2011
Nobel Prize in Chemistry ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then "M ...
was awarded to
Dan Shechtman Dan Shechtman ( he, דן שכטמן; born January 24, 1941)Dan Shechtman
. (PDF). Retriev ...

Dan Shechtman
for the discovery of quasicrystals.


Special properties from anisotropy

Crystals can have certain special electrical, optical, and mechanical properties that
glass Glass is a non- crystalline, often transparency and translucency, transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by ...

glass
and
polycrystal A crystallite is a small or even microscopic crystal A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In phys ...
s normally cannot. These properties are related to the
anisotropy Anisotropy () is the property of a material which allows it to change or assume different properties in different directions as opposed to isotropy. It can be defined as a difference, when measured along different axes, in a material's Physica ...
of the crystal, i.e. the lack of rotational symmetry in its atomic arrangement. One such property is the
piezoelectric effect Piezoelectricity (, ) is the electric charge Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative'' (commonly carrie ...

piezoelectric effect
, where a voltage across the crystal can shrink or stretch it. Another is
birefringence Birefringence is the property of a material having a that depends on the and propagation direction of . These optically materials are said to be birefringent (or birefractive). The birefringence is often quantified as the maximum difference b ...

birefringence
, where a double image appears when looking through a crystal. Moreover, various properties of a crystal, including
electrical conductivity Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current An electric current is a stream of charged particle In p ...
, electrical permittivity, and
Young's modulus Young's modulus E, the Young modulus, or the modulus of elasticity An elastic modulus (also known as modulus of elasticity) is a quantity that measures an object or substance's resistance to being deformed elastically (i.e., non-permanently) wh ...
, may be different in different directions in a crystal. For example,
graphite Graphite (), archaically referred to as plumbago, is a Crystallinity, crystalline form of the element carbon with its atoms arranged in a Hexagonal crystal system, hexagonal structure. It occurs naturally in this form and is the most stable for ...

graphite
crystals consist of a stack of sheets, and although each individual sheet is mechanically very strong, the sheets are rather loosely bound to each other. Therefore, the mechanical strength of the material is quite different depending on the direction of stress. Not all crystals have all of these properties. Conversely, these properties are not quite exclusive to crystals. They can appear in
glass Glass is a non- crystalline, often transparency and translucency, transparent amorphous solid, that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by ...

glass
es or
polycrystal A crystallite is a small or even microscopic crystal A crystal or crystalline solid is a solid Solid is one of the four fundamental states of matter (the others being liquid A liquid is a nearly incompressible fluid In phys ...
s that have been made
anisotropic Anisotropy () is the property of a material which allows it to change or assume different properties in different directions as opposed to isotropy Isotropy is uniformity in all orientations; it is derived from the Greek ''isos'' (ἴσος, ...
by
working Working may refer to: * Work (human activity) Work or labor is intentional activity people perform to support themselves, others, or the needs and wants of a wider community. Alternatively, work can be viewed as the human activity that co ...
or stress—for example,
stress-induced birefringence
stress-induced birefringence
.


Crystallography

''
Crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' "cold drop, frozen drop" ...

Crystallography
'' is the science of measuring the
crystal structure In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' "co ...

crystal structure
(in other words, the atomic arrangement) of a crystal. One widely used crystallography technique is
X-ray diffraction X-ray crystallography (XRC) is the experimental science determining the atomic and molecular structure of a crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a ...
. Large numbers of known crystal structures are stored in crystallographic databases.


Image gallery

File:Insulincrystals.jpg,
Insulin Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets; it is considered to be the main Anabolism, anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats and p ...

Insulin
crystals grown in earth orbit. File:Hoar frost macro2.jpg,
Hoar frost Frost is a thin layer of ice on a solid Solid is one of the four fundamental states of matter (the others being liquid, gas and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic e ...
: A type of ice crystal (picture taken from a distance of about 5 cm). File:Gallium crystals.jpg,
Gallium Gallium is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical elemen ...

Gallium
, a metal that easily forms large crystals. File:Apatite-Rhodochrosite-Fluorite-169799.jpg, An apatite crystal sits front and center on cherry-red rhodochroite rhombs, purple fluorite cubes, quartz and a dusting of brass-yellow pyrite cubes. File:Monokristalines Silizium für die Waferherstellung.jpg,
Boules ''Boules'' () is a collective name for a wide range of games similar to bowls Bowls, or lawn bowls, is a sport Sport pertains to any form of Competition, competitive physical activity or game that aims to use, maintain or improve physic ...
of
silicon Silicon is a chemical element with the Symbol (chemistry), symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a Tetravalence, tetravalent metalloid and semiconductor. It is a member ...

silicon
, like this one, are an important type of industrially-produced
single crystal A single-crystal, or monocrystalline, solid Solid is one of the four fundamental states of matter (the others being liquid, gas and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic e ...
. File:Bornite-Chalcopyrite-Pyrite-180794.jpg, A specimen consisting of a bornite-coated chalcopyrite crystal nestled in a bed of clear quartz crystals and lustrous pyrite crystals. The bornite-coated crystal is up to 1.5 cm across. File:Calcite-millerite association.jpg, Needle-like crystals partially encased in
calcite Calcite is a carbonate mineral Carbonate minerals are those mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid E ...

calcite
crystal and oxidized on their surfaces to zaratite; from the
Devonian The Devonian ( ) is a geologic period and system of the Paleozoic The Paleozoic (or Palaeozoic) Era ( ; from the Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the H ...
Milwaukee Formation of
Wisconsin Wisconsin () is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspaper ...

Wisconsin


See also

*
Atomic packing factor In crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids (see crystal structure). The word "crystallography" is derived from the Greek language, Greek words ''crystallon'' "cold ...
* Anticrystal *
Cocrystal Cocrystals are "solids that are crystalline single phase materials composed of two or more different molecular or ionic compounds generally in a stoichiometric ratio which are neither solvates nor simple salts." A broader definition is that cocrysta ...
* Colloidal crystal *
Crystal growth A crystal 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 addit ...
*
Crystal oscillator A crystal oscillator is an electronic oscillator An electronic oscillator is an electronic circuit 200px, A circuit built on a printed circuit board (PCB). An electronic circuit is composed of individual electronic component An electroni ...

Crystal oscillator
*
Liquid crystal Liquid crystals (LCs) are a state of matter In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time ...
*
Time crystal In condensed matter physics, a time crystal refers to a system or subsystem whose lowest-energy states evolve periodically. This name was proposed theoretically by Frank Wilczek in 2012 as a temporal analog to common crystals, which are periodi ...


References


Further reading

* * * * * {{Authority control