Editing Crystal (section)

== Crystallization ==
{{Main article|Crystallization|Crystal growth}}
[[File:1-cooling-crystallizer-schladen.JPG|thumb|upright|Vertical [[Crystallization|cooling crystallizer]] in a beet sugar factory.]]
Crystallization is the process of forming a crystalline structure from a fluid or from materials dissolved in a fluid. (More rarely, crystals may be [[Deposition (phase transition)|deposited]] directly from gas; see: [[epitaxy]] and [[frost]].)

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]], perhaps with various possible [[phase (matter)|phases]], [[stoichiometries]], impurities, [[Crystallographic defect|defects]], and [[crystal habit|habits]]. Or, it can form a [[polycrystal]], 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]], the [[temperature]], and the speed with which all these parameters are changing.

Specific industrial techniques to produce large single crystals (called ''[[boule (crystal)|boules]]'') include the [[Czochralski process]] and the [[Bridgman technique]]. Other less exotic methods of crystallization may be used, depending on the physical properties of the substance, including [[hydrothermal synthesis]], [[Sublimation (chemistry)|sublimation]], or simply [[Recrystallization (chemistry)|solvent-based crystallization]].

Large single crystals can be created by geological processes. For example, [[Selenite (mineral)|selenite]] crystals in excess of 10&nbsp;[[meter|m]] are found in the [[Cave of the Crystals]] in Naica, Mexico.<ref>{{cite web|url=http://ngm.nationalgeographic.com/2008/11/crystal-giants/shea-text|title=Cave of Crystal Giants |work=National Geographic Magazine |first1=Neil |last1=Shea |date=November 2008 |url-status=dead |archive-url=https://web.archive.org/web/20171219063433/http://ngm.nationalgeographic.com/2008/11/crystal-giants/shea-text |archive-date=Dec 19, 2017 }}</ref> For more details on geological crystal formation, see [[#Rocks|above]].

Crystals can also be formed by biological processes, see [[#Organigenic crystals|above]]. Conversely, some organisms have special techniques to ''prevent'' crystallization from occurring, such as [[antifreeze protein]]s.