{{short description|Visible shape of a mineral}}
{{About|the descriptive term used in mineralogy|the addictive drug|methamphetamine{{!}}crystal methamphetamine}}
[[File:Garnet, quartz, feldspar 8.jpg|thumb|upright=1.35|[[Smoky quartz]] with [[spessartine]] on top of [[feldspar]] matrix, featuring different crystal habits (shapes)]]

In [[mineralogy]], '''crystal habit''' is the characteristic external shape of an individual [[crystal]] or aggregate of crystals. The habit of a crystal is dependent on its [[crystallographic form]] and growth conditions, which generally creates irregularities due to limited space in the [[Crystallization|crystallizing]] medium (commonly in [[Rock (geology)|rocks]]).<ref name="Klein">Klein, Cornelis, 2007, ''Minerals and Rocks: Exercises in Crystal and Mineral Chemistry, Crystallography, X-ray Powder Diffraction, Mineral and Rock Identification, and Ore Mineralogy,'' Wiley, third edition, {{ISBN|978-0471772774}}</ref><ref name="Wenk">Wenk, Hans-Rudolph and Andrei Bulakh, 2004, ''Minerals: Their Constitution and Origin,'' Cambridge, first edition, {{ISBN|978-0521529587}}</ref>

==Crystal forms==
Recognizing the habit can aid in mineral identification and description, as the crystal habit is an external representation of the [[Crystal structure|internal ordered atomic arrangement]].<ref name="Klein" /> Most natural crystals, however, do not display ideal habits and are commonly malformed. The quality of the shape of a crystal in a mineral specimen can be described as one of the following:

* [[Euhedral]]: a crystal that is completely bounded by its characteristic faces, well-formed. Synonymous terms: idiomorphic, automorphic;
* [[Subhedral]]: a crystal partially bounded by its characteristic faces and partially by irregular surfaces. Synonymous terms: hypidiomorphic, hypautomorphic;
* [[Anhedral (petrology)|Anhedral]]: a crystal that lacks any of its characteristic faces, completely malformed. Synonymous terms: allotriomorphic, xenomorphic.

==Altering factors==
[[File:Goethite-Pyrite-44341.jpg|thumb|left|[[Goethite]] replacing [[pyrite]] cubes]]
Factors influencing habit include: a combination of two or more crystal forms; trace impurities present during growth; [[crystal twinning]] and growth conditions (i.e., heat, pressure, space); and specific growth tendencies such as growth [[striation (geology)|striations]]. Minerals belonging to the same [[crystal system]] do not necessarily exhibit the same habit. Some habits of a mineral are unique to its variety and locality: For example, while most [[sapphire]]s form elongate barrel-shaped crystals, those found in [[Montana]] form stout ''tabular'' crystals. Ordinarily, the latter habit is seen only in [[ruby]]. Sapphire and ruby are both varieties of the same mineral: [[corundum]].

Some minerals may replace other existing minerals while preserving the original's habit, i.e. [[Pseudomorph|pseudomorphous replacement]]. A classic example is [[tiger's eye]] quartz, crocidolite [[asbestos]] replaced by [[silica]]. While [[quartz]] typically forms ''prismatic'' (elongate, prism-like) crystals, in tiger's eye the original ''fibrous'' habit of [[crocidolite]] is preserved.
{{clear}}

==List of crystal habits==
<ref>{{Cite web |url=http://www.galleries.com/minerals/property/habits.htm |title=What are descriptive crystal habits |access-date=2009-04-06 |archive-url=https://web.archive.org/web/20170707071537/http://www.galleries.com/minerals/property/habits.htm |archive-date=2017-07-07 |url-status=dead }}</ref>{{Better source needed|date=January 2023}}<ref>[http://www.khulsey.com/jewelry/crystal_habit.html Crystal Habit] {{webarchive|url=https://web.archive.org/web/20090412012420/http://www.khulsey.com/jewelry/crystal_habit.html |date=2009-04-12 }}</ref>{{Better source needed|date=January 2023}}<ref>{{Cite web |url=http://www.gemstonebuzz.com/habit |title=Habit |access-date=2009-04-06 |archive-date=2017-12-01 |archive-url=https://web.archive.org/web/20171201031004/http://www.gemstonebuzz.com/habit |url-status=dead }}</ref>{{Better source needed|date=January 2023}}<ref>{{cite journal| last1=Hanaor| first1=D.A.H|  last2=Xu| first2=W|last3=Ferry|first3=M|last4=Sorrell|first4=CC | title= Abnormal grain growth of rutile TiO<sub>2</sub> induced by ZrSiO| journal= Journal of Crystal Growth| year= 2012| volume=359| pages=83–91| doi=10.1016/j.jcrysgro.2012.08.015|arxiv=1303.2761|bibcode=2012JCrGr.359...83H| s2cid=94096447}}</ref>

===Aggregate habits===
{| class="wikitable"
!Habit
!Image
!Description
!Common example(s)
|-
|[[Acicular (crystal habit)|Acicular]]
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Natroliteinde1.jpg| caption1 = [[Natrolite]]
| image2 = Scolécite (Inde) 2.JPG| caption2 = [[Scolecite]]
}}
|Needle-like, slender, and end-tapered prisms growing in a radial/globular fashion.
|[[natrolite]], [[scolecite]], [[yuanfuliite]]
|-
|Arborescent
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Acanthite-Silver-imiter4.jpg| caption1 = [[Native silver]]
| image2 = Or Venezuela.jpg| caption2 = [[Gold]]
}}
|Tree-like crystals growing similar to branches.
|[[Native copper]], [[gold]], [[native silver]]
|-
|Capillary/Filiform 
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Byssolite France.jpg| caption1 = [[Byssolite]]
| image2 = Millerite in geode (Harrodsburg, Indiana, USA).jpg| caption2 = [[Millerite]]
}}
|Hair-like or thread-like, extremely fine 
| [[byssolite]], [[millerite]]
|-
|Colloform/Nodular/Tuberose
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Agate (Adrasman City, Tajikistan) (32755918215).jpg| caption1 = [[Agate]]
| image2 = Objektfotografie in Styrobox-Schalenblende-1.jpg| caption2 = [[Sphalerite]]
}}
|Rounded, finely banded deposits with irregular concentric protuberances
| [[agate]], [[baryte]], [[sphalerite]]
|-
|Concentric
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Amethyst (14902840630).jpg| caption1 = [[Amethyst]]
| image2 = Rhodocrosite, da capilitas, argentina.JPG| caption2 = [[Rhodocrosite]]
}}
|Circular ring aggregates around a center. This habit is found in cross-sections from reniform/mamillary habits, and also from elongated stalactites of [[amethyst]] (quartz), malachites, rhodocrosite, and others
|[[agate]], [[quartz]], [[malachite]], [[rhodocrosite]]
|-
|Dendritic
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Copper (Mesoproterozoic, 1.05-1.06 Ga; Baltic Mine, Baltic, Michigan, USA).jpg| caption1 = [[Native copper]]
| image2 = Psilomelane-pyrolusite 7100.4900.jpg| caption2 = [[Romanechite]]
}}
|Root-like, branching in one or more direction from central point
| [[Native copper]], [[gold]], [[romanechite]], [[magnesite]], [[native silver]]
|-
|[[Druse (geology)|Druse]]/Encrustation
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Celestine5 (Battistini Riccardo).jpg| caption1 = [[Celestine (mineral)|Celestine]]
| image2 = Muséum de Nantes - 352 - Calcite (Grenoble, Isère, France).jpg| caption2 = [[Calcite]]
}}
|Aggregate of crystals coating a surface or cavity, usually found in [[geode]]s and some [[fossil]]s
|[[azurite]], [[Celestine (mineral)|celestine]], [[calcite]], [[uvarovite]], [[malachite]], [[quartz]]
|-
|Fibrous/[[Asbestiform]]
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Estonian Museum of Natural History Specimen No 195150 photo (g57 g57-65 jpg).jpg| caption1 = [[Tremolite]]
| image2 = Baryt-harz hg.jpg| caption2 = [[Baryte]]
}}
|Extremely slender prisms forming muscle-like fibers
|[[actinolite]], [[asbestos]], [[baryte]], [[kyanite]], [[gypsum]], [[nitratine]], [[stilbite]], [[serpentine group]]
|-
|Foliated/Micaceous/Lamellar
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Molly Hill molybdenite.JPG| caption1 = [[Molybdenite]]
| image2 = MeroxeneSomma.png| caption2 = [[Biotite]]
}}
|Layered crystal planes, parting into thin sheets
|[[biotite]], [[hematite]], [[muscovite]], [[lepidolite]], [[molybdenite]]
|-
|Granular
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Granat (uwarowit) - Saranowskiy Mine, Ural.jpg| caption1 = [[Uvarovite]]
| image2 = Quartz geode 4.jpg| caption2 = [[Quartz]]
}}
|Aggregates of diminute anhedral crystals in [[Matrix (geology)|matrix]] or other surface
|[[andradite]], [[bornite]], [[scheelite]], [[quartz]], [[uvarovite]]
|-
|[[Hopper crystal|Hopper]]
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Halite.jpg| caption1 = [[Halite]]
| image2 = Bismuth Crystals.JPG| caption2 = [[Bismuth]]
}}
|Outer portions of cubes grow faster than inner portions, creating a concavity similar to that of a [[Hopper (particulate collection container)|hopper]]
|[[bismuth]] (artificial), [[halite]], [[galena]]
|-
|Oolithic
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Oolitic limestone (Salem Limestone, Middle Mississippian; southern Indiana, USA) 1.jpg| caption1 = [[Calcite]]
| image2 = OoidSurface01.jpg| caption2 = [[Calcite]]
}}
|Small spheres or grains (commonly flattened) that resemble eggs
|[[aragonite]], [[calcite]]
|-
|Pisolitic
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Chertified pisolitic bauxite (wet, cut surface; 11.7 cm across) from Arkansas, USA.jpg| caption1 = [[Bauxite]]
| image2 = PisolitesConococheagueUpperCambrian.jpg| caption2 = [[Pisolite]]
}}
|Rounded concentric nodules often found in sedimentary rocks. Much larger than oolithic
| [[aragonite]], [[bauxite]], [[calcite]], [[pisolite]]
|-
|Platy/Tabular/Blocky
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Baryte NHMLA 2.png| caption1 = [[Baryte]]
| image2 = Wulfenite mexique.jpg| caption2 = [[Wulfenite]]
}}
|Flat, tablet-shaped, prominent pinnacoid
|[[baryte]], [[feldspar]], [[topaz]], [[vanadinite]], [[wulfenite]]
|-
|Plumose
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Aurichalcite79 Mine.jpg| caption1 = [[Aurichalcite]]
| image2 = Okenite, prehnite 2.jpg| caption2 = [[Okenite]]
}}
|Fine, feather-like scales
|[[aurichalcite]], [[okenite]], [[mottramite]]
|-
|Radial/Radiating/Divergent
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Atacamite from La Farola Mine, Chile.jpg| caption1 = [[Atacamite]]
| image2 = Pyrophyllite-552742.png| caption2 = [[Pyrophyllite]]
}}
|Radiating outward from a central point without producing a star (crystals are generally separated and have different lengths).
|[[aenigmatite]], [[atacamite]], [[epidote]], [[pyrophyllite]], [[stibnite]]
|-
|Reticulated
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Cerussit aus Ems, Ausschnitt.jpg| caption1 = [[Cerussite]]
| image2 = Rutile sur hématite (Brésil).jpg| caption2 = [[Rutile]]
}}
|Crystals forming triangular net-like intergrowths.
|[[cerussite]], [[rutile]]
|-
|Rosette/Lenticular
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Desert rose 3.jpg| caption1 = [[Baryte]]
| image2 = Desert flower.jpg| caption2 = [[Gypsum]]
}}
|Platy, radiating rose-like aggregate (also lens shaped crystals)
|[[gypsum]], [[baryte]], [[calcite]]
|-
|Stalactitic
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Quartz-Chrysocolla-206925.jpg| caption1 = [[Chrysocolla]]
| image2 = Calcite 7.jpg| caption2 = [[Calcite]]
}}
|Forming as [[stalactite]]s or [[stalagmite]]s; cylindrical or cone-shaped. Their cross-sections often reveal a "concentric" pattern
|[[calcite]], [[chalcedony]], [[chrysocolla]], [[goethite]], [[malachite]], [[romanechite]]
|-
|Stellate
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Goethite-hematite (Biwabik Iron-Formation, Paleoproterozoic, ~1.878 Ga; Embarass Mine, Mesabi Iron Range, Minnesota, USA) 6 (33825160504).jpg| caption1 = [[Hematite]]
| image2 = Wavellite (Arkansas - USA) 2.JPG| caption2 = [[Wavellite]]
}}
|Star-like, radial fibers found inside spherical habits, such as mamillary or reniform.
| [[hematite]], [[pectolite]], [[shattuckite]], [[wavellite]]
|-
|}

===Asymmetrical/Irregular habits===
{| class="wikitable"
!Habit
!Image
!Description
!Common example(s)
|-
|[[Amygdule|Amygdaloidal]]
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = HeulanditeLonavala.jpg| caption1 = [[Heulandite]]
| image2 = StilbiteInde3.jpg| caption2 = [[Stilbite]]
}}
|Like embedded [[almond]]s
|[[heulandite]], [[stilbite]], [[zircon]]
|-
|Hemimorphic
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Hemimorphite rosazite.jpg| caption1 = [[Hemimorphite]]
| image2 = Forsterite-Olivine-tmu14a.jpg| caption2 = [[Olivine]]
}}
|Doubly terminated crystal with two differently shaped ends
|[[elbaite]], [[hemimorphite]], [[olivine]]
|-
|Massive/Compact
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Turquoise, pyrite, quartz 300-4-FS.jpeg| caption1 = [[Turquoise]]
| image2 = Quartz rose cristallisé sur quartz (Brésil) 3.JPG| caption2 = [[Quartz]]
}}
|Shapeless, no distinctive external crystal shape
|[[limonite]], [[turquoise]], [[cinnabar]], [[quartz]], [[realgar]], [[lazurite]]
|-
|Sceptered
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Améthyste sceptre1 (Madagascar).jpg| caption1 = [[Amethyst]]
| image2 = Cérusite, barytine 300.3.7200.jpg| caption2 = [[Baryte]]
}}
|Crystal growth stops and continues at the top of the crystal, but not at the bottom. Exceptional aggregates of this habit (such as quartz) are often referred as "Elestial".
|[[baryte]], [[calcite]], [[marcasite]], [[quartz]]
|-
|}

===Symmetrical habits===
{| class="wikitable"
!Habit
!Image
!Description
!Common example(s)
|-
|Cubic
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Selpologne.jpg| caption1 = [[Halite]]
| image2 = Pyrite-8859.jpg| caption2 = [[Pyrite]]
}}
|[[Cube]]-shaped
|[[fluorite]], [[pyrite]], [[galena]], [[halite]]
|-
|Dodecahedral
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Pyrite elbe.jpg| caption1 = [[Pyrite]]
| image2 = Almandine J2.jpg| caption2 = [[Almandine]]
}}
|[[Dodecahedron]]-shaped, 12-sided. Central facet can vary.
|[[garnet]], [[pyrite]]
|-
|Enantiomorphic
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Aragonite, goethite.jpg| caption1 = [[Aragonite]]
| image2 = Staurolite 002.jpg| caption2 = [[Staurolite]]
}}
|Mirror-image habit (i.e. [[crystal twinning]]) and optical characteristics; right- and left-handed crystals
|[[aragonite]], [[gypsum]], [[quartz]], [[plagioclase]], [[staurolite]]
|-
|Hexagonal
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Vanadinite, goethite 5.jpg| caption1 = [[Vanadinite]]
| image2 = Galena-calcite (Huanzala Mine, Peru) 2.jpg| caption2 = [[Galena]]
}}
|[[Hexagon]]al prism (six-sided)
|[[beryl]], [[galena]], [[quartz]], [[hanksite]], [[vanadinite]]
|-
|Icositetrahedral
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Granat (garnet), spessartyn - Fujien, Yun-Xiao, Chiny.JPG| caption1 = [[Spessartine]]
| image2 = Analcime provenanceInconnue Refn°505483 MuséumHistoireNaturelleLille GLAM2016 Photo.F.Lamiot HD.jpg| caption2 = [[Analcime]]
}}
|[[Deltoidal icositetrahedron|Icositetrahedron]]-shaped, 24-faced
|[[analcime]], [[spessartine]]
|-
|Octahedral
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Spinelle, calcite 7.JPG| caption1 = [[Spinel]]
| image2 = Fluorine (Mexique) 7.JPG| caption2 = [[Fluorite]]
}}
|[[Octahedron]]-shaped, square [[bipyramid]] (eight-sided)
|[[diamond]], [[fluorine]], [[fluorite]], [[magnetite]], [[pyrite]]
|-
|Prismatic
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Beryl-erongoberylbicolor1.jpg| caption1 = [[Beryl]]
| image2 = Tourmaline paraïba (Brésil) 1.JPG| caption2 = [[Tourmaline]]
}}
|Elongate, prism-like: may or not present well-developed crystal faces parallel to the vertical axis
|[[beryl]], [[tourmaline]], [[vanadinite]]
|-
|Rhombohedral
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Galena-Quartz-Siderite-tuc1028e.jpg| caption1 = [[Siderite]]
| image2 = Rhodochrosite Alma MNHN Minéralogie.jpg| caption2 = [[Rhodochrosite]]
}}
|[[Rhombohedron]]-shaped (six-faced rhombi)
|[[calcite]], [[magnesite]], [[rhodochrosite]], [[siderite]]
|-
|Scalenohedral
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Calcite jaune sur fluorine violette (USA).jpg| caption1 = [[Calcite]]
| image2 = Rhodocrosite (Pérou) 2.jpg| caption2 = [[Rhodochrosite]]
}}
|[[Scalenohedron]]-shaped, pointy ends
|[[calcite]], [[rhodochrosite]], [[titanite]]
|-
|Tetrahedral
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Sphalerite-221270.jpg| caption1 = [[Sphalerite]]
| image2 = Tetrahedrite-Chalcopyrite-Sphalerite-251531.jpg| caption2 = [[Tetrahedrite]]
}}
|[[Tetrahedron]]-shaped, triangular pyramid (four-sided)
|[[chalcopyrite]], [[tetrahedrite]], [[sphalerite]], [[magnetite]]
|-
|}

===Rounded/Spherical habits===
{| class="wikitable"
!Habit
!Image
!Description
!Common example(s)
|-
|[[Botryoidal]]
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Botryoidal Purple Grape Agate Chalcedony from Indonesia.jpg| caption1 = [[Chalcedony]]
| image2 = Calcite (Cave-in-Rock Mining District, Illinois, USA) 2 (42590140235).jpg| caption2 = [[Calcite]]
}}
|Grape-like, large and small hemispherical masses, nearly differentiated/separated from each other
|[[calcite]], [[chalcedony]], [[halite]], [[plumbogummite]], [[smithsonite]]
|-
|Globular
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Gyrolite 5(Inde).jpg| caption1 = [[Gyrolite]]
| image2 = Globular calcite on quartz.jpg| caption2 = [[Calcite]]
}}
|Isolated hemispheres or spheres
|[[calcite]], [[fluorite]], [[gyrolite]]
|-
|Mammillary
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Agate Chalcedony GE9323 540427.jpg| caption1 = [[Chalcedony]]
| image2 = Hematite 3.jpg| caption2 = [[Hematite]]
}}
|Breast-like: surface formed by intersecting partial spherical shapes, larger version of botryoidal and/or reniform, also concentric layered aggregates.
|[[chalcedony]], [[hematite]], [[malachite]]
|-
|Reniform
|{{Image array
| perrow = 2
| width = 150
| height = 150
| border-width = 2
| image1 = Malachite Congo 4 Luc Viatour.jpg| caption1 = [[Malachite]]
| image2 = Hematite (GeoDIL number - 1382).jpg| caption2 = [[Hematite|Hematite (kidney ore)]]
}}
|Irregular [[kidney]]-shaped spherical masses
|[[cassiterite]], [[chalcedony]], [[chrysocolla]], [[hematite]], [[hemimorphite]] [[fluorite]], [[goethite]], [[greenockite]], [[malachite]], [[rhodochrosite]], [[smithsonite]], [[mottramite]], [[wavellite]]
|-
|}

==See also==
*[[Abnormal grain growth]]
*[[Grain growth]]
*[[Crystal structure]]

==References==
{{reflist}}

== Bibliography ==
* {{cite book |first1= Ivan |last1= Kostov |author-link= Ivan Kostov Nikolov |first2= Ruslan I. |last2= Kostov |title= Crystal Habits of Minerals |place= Sofia |publisher=  Academic Publishing House "Prof. Marin Drinov" |year= 1999|oclc = 488807766 |isbn= 9789546420602}}

{{Mineral identification}}

{{Authority control}}

[[Category:Crystallography]]
[[Category:Mineralogy concepts]]
[[Category:Mineral habits]]