efflorescence

(chemistry) The formation of a powdery surface on crystals, as a hydrate is converted to anhydrous form by losing loosely bound water of crystallization to the atmosphere.

(botany) The production of flowers.

(construction) An encrustation of soluble salts, commonly white, deposited on the surface of stone, brick, plaster, or mortar; usually caused by free alkalies leached from mortar or adjacent concrete as moisture moves through it.

(geology) An encrustation of soluble salts, deposited on rock or soil by evaporation; often found in arid or geothermal environments.

(figuratively) Rapid flowering of a culture or civilisation etc.

(pathology) A redness, rash, or eruption on the skin.