Efflorescence

In chemistry, efflorescence (which means 'to flower out' in French) is the migration of a 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.Primary efflorescence on a brick wall in Germany.Primary efflorescence on a firestop mortar at Mississauga Civic Centre in Mississauga, Ontario City Hall.Substantial primary efflorescence on a building in Denver, Colorado.Secondary efflorescence - dissolving the cement stone and attacking rebarSecondary efflorescenceConcrete derived secondary deposit of calcium carbonate creating calthemite stalactites, which can be mistakenly confused with efflorescence. In chemistry, efflorescence (which means 'to flower out' in French) is the migration of a 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.