A

• Adcumulate
• Agglomeritic
  Agglomerate
  Agglomerates are coarse accumulations of large blocks of volcanic material that contain at least 75% bombs...
  
  
• Adamantine a type of lustre
  Lustre (mineralogy)
  Lustre is a description of the way light interacts with the surface of a crystal, rock, or mineral. The word lustre traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance....
  
  
• Amygdaloidal
  Amygdule
  Amygdules or amygdales form when the gas bubbles or vesicles in volcanic lava are infilled with a secondary mineral such as calcite, quartz, chlorite or one of the zeolites. Amygdules usually form after the rock has been emplaced, and are often associated with low-temperature alteration. Amygdules...
  
  
• Anhedral
  Anhedral (petrology)
  A rock with an anhedral texture is composed of mineral grains that have no well formed crystal faces or cross-section shape in thin section. Anhedral crystal growth occurs in a competitive environment with no free space for the formation of crystal faces. An intermediate texture with some crystal...
  
  
• Antitaxial veins
• Aphanitic
• Aplitic
  Aplite
  Aplite in petrology, the name given to intrusive rock in which quartz and feldspar are the dominant minerals. Aplites are usually very fine-grained, white, grey or pinkish, and their constituents are visible only with the help of a magnifying lens...
  
  ; aplite
• Augen textured gneiss
  Augen
  Augen are large, lenticular eye-shaped mineral grains or mineral aggregates visible in some foliated metamorphic rocks. In cross section they have the shape of an eye.Feldspar, quartz, and garnet are common minerals which form augen....
  
  
• Axiolitic texture

B

• Botryoidal
  Botryoidal
  A botryoidal texture or mineral habit is one in which the mineral has a globular external form resembling a bunch of grapes as derived from the Greek. This is a common form for many minerals particularly hematite where it is the classically recognized shape. It is also a common form of goethite,...
  
  
• breccia
  Breccia
  Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix, that can be either similar to or different from the composition of the fragments....
  
  ted
• Bedding fissile
  Foliation (geology)
  Foliation is any penetrative planar fabric present in rocks. Foliation is common to rocks affected by regional metamorphic compression typical of orogenic belts. Rocks exhibiting foliation include the standard sequence formed by the prograde metamorphism of mudrocks; slate, phyllite, schist and...
  
  ; bedding fissility
• Boudinage
  Boudinage
  thumb|Boudinaged quartz vein in shear foliation, Starlight Pit, Fortnum Gold Mine, Western Australia.Boudinage is a geological term for structures formed by extension, where a rigid tabular body such as a bed of sandstone, is stretched and deformed amidst less competent surroundings...
  
  ; boudins
  Boudinage
  thumb|Boudinaged quartz vein in shear foliation, Starlight Pit, Fortnum Gold Mine, Western Australia.Boudinage is a geological term for structures formed by extension, where a rigid tabular body such as a bed of sandstone, is stretched and deformed amidst less competent surroundings...
  
  

C

• Cataclastic
• Chilled margin
  Chilled margin
  A chilled margin is a shallow intrusive or volcanic rock texture characterised by a glassy or fine grained zone along the margin where the magma or lava has contacted air, water, or particularly much cooler rock. This is caused by rapid crystallization of the melt near the contact with the...
  
  
• Clastic; see also breccia
  Breccia
  Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix, that can be either similar to or different from the composition of the fragments....
  
  
• Cleaved
  Cleavage (geology)
  This article is about rock cleavage, for cleavage in minerals see Cleavage Cleavage, in structural geology and petrology, describes a type of planar rock feature that develops as a result of deformation and metamorphism. The degree of deformation and metamorphism along with rock type determines the...
  
  
• Crenulated
  Crenulation
  Crenulation or Crenulation cleavage is a texture formed in metamorphic rocks such as phyllite, schist and some gneiss by two or more stress directions resulting in superimposed foliations.-Formation:...
  
  
• Cross-bedding
  Cross-bedding
  In geology, the sedimentary structures known as cross-bedding refer to horizontal units that are internally composed of inclined layers. This is a case in geology in which the original depositional layering is tilted, and the tilting is not a result of post-depositional deformation...
  
  
• Cross-stratification; also trough-cross stratification.
• Cumulate
  Cumulate rock
  Cumulate rocks are igneous rocks formed by the accumulation of crystals from a magma either by settling or floating. Cumulate rocks are named according to their texture; cumulate texture is diagnostic of the conditions of formation of this group of igneous rocks.-Formation:Cumulate rocks are the...
  
  ; see also layered intrusion

D

• Decussate
• Devitirification; devitrified
• Dendritic texture; dendrites
• Diatextite
  Schlieren
  Schlieren are optical inhomogeneities in transparent material not visible to the human eye. Schlieren physics developed out of the need to produce high-quality lenses devoid of these inhomogeneities. These inhomogeneities are localized differences in optical path length that cause light deviation...
  
  ; see also schlieren
  Schlieren
  Schlieren are optical inhomogeneities in transparent material not visible to the human eye. Schlieren physics developed out of the need to produce high-quality lenses devoid of these inhomogeneities. These inhomogeneities are localized differences in optical path length that cause light deviation...
  
   and migmatite
  Migmatite
  Migmatite is a rock at the frontier between igneous and metamorphic rocks. They can also be known as diatexite.Migmatites form under extreme temperature conditions during prograde metamorphism, where partial melting occurs in pre-existing rocks. Migmatites are not crystallized from a totally...
  
  

E

• Embayed minerals; see igneous texture
  Rock microstructure
  Rock microstructure includes the texture of a rock and the small scale rock structures. The words "texture" and "microstructure" are interchangeable, with the latter preferred in modern geological literature...
  
  
• Euhedral
  Euhedral
  Euhedral crystals are those that are well-formed with sharp, easily recognised faces. Normally, crystals do not form smooth faces or sharp crystal outlines. Many crystals grow from cooling liquid magma...
  
  
• Eutaxitic
• Epiclastic

F

• Fiamme
  Fiamme
  Fiamme are lens-shapes, usually mm to cm in size, seen on surfaces of some volcaniclastic rocks. They can occur in welded pyroclastic fall deposits and in ignimbrites, which are the deposits of pumiceous pyroclastic density currents. The name fiamme comes from the Italian word for flames,...
  
  
• Foliation
  Foliation (geology)
  Foliation is any penetrative planar fabric present in rocks. Foliation is common to rocks affected by regional metamorphic compression typical of orogenic belts. Rocks exhibiting foliation include the standard sequence formed by the prograde metamorphism of mudrocks; slate, phyllite, schist and...
  
  
• Fissile
  Fissile
  In nuclear engineering, a fissile material is one that is capable of sustaining a chain reaction of nuclear fission. By definition, fissile materials can sustain a chain reaction with neutrons of any energy. The predominant neutron energy may be typified by either slow neutrons or fast neutrons...
  
  ; see also Bedding fissility
  Foliation (geology)
  Foliation is any penetrative planar fabric present in rocks. Foliation is common to rocks affected by regional metamorphic compression typical of orogenic belts. Rocks exhibiting foliation include the standard sequence formed by the prograde metamorphism of mudrocks; slate, phyllite, schist and...
  
  .
• Fossil
  Fossil
  Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
  
  iferous

G

• Glomeroporphyritic
  Glomeroporphyritic
  In geology, the term glomeroporphyritic refers to the grouping of phenocrysts, not necessarily of the same mineral, into distinct clusters within porphyritic igneous rocks....
  
  
• Gneiss
  Gneiss
  Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks.-Etymology:...
  
  ose; gneissic
• Granoblastic
  Granoblastic
  Granoblastic is an anhedral phaneritic equi-granular metamorphic rock texture. Granoblastic texture is typical of quartzite, marble and other non-foliated metamorphic rocks without porphyroblasts. Characteristics defining granoblastic texture include: grains visible to the unaided eye, sutured...
  
  
• Granophyric
  Granophyre
  Granophyre is a subvolcanic rock that contains quartz and alkali feldspar in characteristic angular intergrowths such as those in the accompanying image....
  
  
• Granulitic
  Granulite
  Granulites are medium to coarse–grained metamorphic rocks that have experienced high temperature metamorphism, composed mainly of feldspars sometimes associated with quartz and anhydrous ferromagnesian minerals, with granoblastic texture and gneissose to massive structure...
  
  
• Graphic
  Graphic texture
  Graphic texture is commonly created by exsolution and devitrification and immiscibility processes in igneous rocks.It is called 'graphic' because the exsolved or devitrified minerals form wriggly lines and shapes which are reminiscent of writing....
  
  

L

• Lepidoblastic
• Leucocratic; see also melanocratic
• Lineation, lineated
• L-tectonite
  Tectonite
  Tectonites are metamorphic or tectonically deformed rocks whose fabric reflects the history of their deformation, or rocks with fabric that clearly displays coordinated geometric features that indicate continuous solid flow during formation. Planar foliation results from a parallel orientation of...
  
  

O

• Ocelli
• oolitic
  Oolite
  Oolite is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Hellenic word òoion for egg. Strictly, oolites consist of ooids of diameter 0.25–2 mm; rocks composed of ooids larger than 2 mm are called pisolites...
  
  ; see also limestone
  Limestone
  Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
  
  
• Ophitic texture
• Orbicular texture
• Orthocumulate

P

• Panidiomorphic
• Perthitic
  Perthite
  Perthite is used to describe an intergrowth of two feldspars: a host grain of potassium-rich alkali feldspar includes exsolved lamellae or irregular intergrowths of sodic alkali feldspar . Typically the host grain is orthoclase or microcline, and the lamellae are albite...
  
  
• Phaneritic
  Phaneritic
  Phaneritic is a term usually used to refer to igneous rock grain size. It means that the size of matrix grains in the rock are large enough to be distinguished with the unaided eye as opposed to aphanitic . This texture forms by slow cooling of magma deep underground in the plutonic environment...
  
  
• Phyllitic
  Phyllite
  Phyllite is a type of foliated metamorphic rock primarily composed of quartz, sericite mica, and chlorite; the rock represents a gradation in the degree of metamorphism between slate and mica schist. Minute crystals of graphite, sericite, or chlorite impart a silky, sometimes golden sheen to the...
  
  
• Pisolitic
  Pisolite
  A pisolite is a sedimentary rock made of pisoids, which are concretionary grains - often of calcium carbonate, but sometimes of rarer minerals - which resemble ooids but are always more than 2 mm in diameter. These grains are approximately spherical and have concentric layers reaching...
  
  
• Porphyroclast
  Porphyroclast
  thumb|350px|right|A [[mylonite]] showing a number of porphyroclasts: a clear red [[garnet]] left in the picture while smaller white [[feldspar]] porphyroclasts can be found all over...
  
  ic
• Porphyroblast
  Porphyroblast
  A porphyroblast is a large mineral crystal in a metamorphic rock which has grown within the finer grained groundmass. Porphyroblasts are commonly euhedral crystals, but can also be partly to completely irregular in shape....
  
  ic
• Porphyritic texture
  Porphyritic
  Porphyritic is an adjective used in geology, specifically for igneous rocks, for a rock that has a distinct difference in the size of the crystals, with at least one group of crystals obviously larger than another group...
  
  ; see also porphyry
  Porphyry (geology)
  Porphyry is a variety of igneous rock consisting of large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass. The larger crystals are called phenocrysts...
  
  
• Ptygmatic (folding); see migmatite
  Migmatite
  Migmatite is a rock at the frontier between igneous and metamorphic rocks. They can also be known as diatexite.Migmatites form under extreme temperature conditions during prograde metamorphism, where partial melting occurs in pre-existing rocks. Migmatites are not crystallized from a totally...
  
  

S

• Sand
  Sand
  Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...
  
  y
• Schistose; schistosity
• Shear; sheared; shear fabric
• Slaty
  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. The result is a foliated rock in which the foliation may not correspond to the original sedimentary layering...
  
  ; slaty cleavage
• Specular
• Spinifex texture; see also komatiite
  Komatiite
  Komatiite is a type of ultramafic mantle-derived volcanic rock. Komatiites have low silicon, potassium and aluminium, and high to extremely high magnesium content...
  
  
• S-tectonite
  Tectonite
  Tectonites are metamorphic or tectonically deformed rocks whose fabric reflects the history of their deformation, or rocks with fabric that clearly displays coordinated geometric features that indicate continuous solid flow during formation. Planar foliation results from a parallel orientation of...
  
  
• Stratabound
• Stratiform
• Stromatolitic
  Stromatolite
  Stromatolites or stromatoliths are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria ....
  
  
• Stylolitic
  Stylolite
  Stylolites are serrated surfaces at which mineral material has been removed by pressure dissolution, in a process that decreases the total volume of rock. Insoluble minerals like clays, pyrite, oxides remain within the stylolites and make them visible...
  
  
• Subhedral
  Euhedral
  Euhedral crystals are those that are well-formed with sharp, easily recognised faces. Normally, crystals do not form smooth faces or sharp crystal outlines. Many crystals grow from cooling liquid magma...
  
  
• Symplectite
  Symplectite
  In mineralogy, a symplectite is a very fine intergrowth of two or more distinct mineral phases. Symplectites are largely considered to result from the breakdown of unstable minerals....
  
  

V

• Vesicular texture
  Vesicular texture
  Vesicular texture is a volcanic rock texture characterised by a rock being pitted with many cavities at its surface and inside. The texture is often found in extrusive aphanitic, or glassy, igneous rock...
  
  
• Variolitic
  Variolite
  Variolites are a group of dark green basic igneous rocks that, especially on weathered surfaces, exhibit pale colored spots, or spherules, that give them a pockmarked appearance...
  
  
• Vitreous
• Vug
  Vug
  Vugs are small to medium-sized cavities inside rock that may be formed through a variety of processes. Most commonly cracks and fissures opened by tectonic activity are partially filled by quartz, calcite, and other secondary minerals. Open spaces within ancient collapse breccias are another...
  
  gy

See also

• List of minerals
• Rock microstructure
  Rock microstructure
  Rock microstructure includes the texture of a rock and the small scale rock structures. The words "texture" and "microstructure" are interchangeable, with the latter preferred in modern geological literature...
  
  
• List of rock types
• Crystallography
  Crystallography
  Crystallography is the experimental science of the arrangement of atoms in solids. The word "crystallography" derives from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and grapho = write.Before the development of...