Efflorescence is the loss of water (or a solvent) of crystallization from a hydrated or solvated salt to the atmosphere on exposure to air.Efflorescence 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 comprises 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.Example is Gypsum (CaSO4.2H2O) is a hydrate solid that, in a sufficiently dry environment, will give up its water to the gas phase and forms anhydrite (CaSO4).
In chemistry effloresence is migration of salt to a surface of porous material where it form coating.
I know effervescence
Effloresence or effervescence