Editing Efflorescence (section)

{{Short description|Migration of a salt to the surface of a porous material}}
{{redirect|Effloresce|the album by Oceansize|Effloresce (album)}}
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[[Image:Robert moses secondary efflorescence 2.jpg|thumb|right|300px|Secondary efflorescence on the dam of the [[Robert Moses Niagara Power Plant]].]]
In [[chemistry]], '''efflorescence''' (Derived from the Latin verb 'efflorescere' roughly meaning 'to flower') is the migration of a [[Salt (chemistry)|salt]] to the surface of a porous material, where it forms a coating. The essential process involves the dissolving of an internally held salt in water or occasionally, in another solvent. The water, with the salt now held in solution, migrates to the surface, then evaporates, leaving a coating of the salt.

In what has been described as "primary efflorescence", the water is the invader and the salt was already present internally, and a reverse process, where the salt is originally present externally and is then carried inside in solution, is referred to as "secondary efflorescence".

Efflorescences can occur in natural and built environments. On porous construction materials it may present a cosmetic outer problem only (primary efflorescence causing staining), but can sometimes indicate internal structural weakness (migration/degradation of component materials).<ref>{{cite web |title=Efflorescence for Inspectors |url=https://www.nachi.org/efflorescence.htm |website=International Association of Certified Home Inspectors}}</ref>  Efflorescence may clog the pores of porous materials, resulting in the destruction of those materials by internal water pressure, as seen in the [[spall|spalling]] of brick.