In chemistry, the term blooming refers to the appearance of white or colored crystals or deposits on the surface of materials such as metals, glass or ceramics. These deposits are caused by the evaporation of substances that are volatile at room temperature, such as salts or acids.

Blooming occurs when the volatiles in the air evaporate and settle on the surface of the material. When the substances come into contact with moisture, they can react and form crystals that become visible as efflorescence on the surface.

Efflorescence can occur Corrosion and material damage and are therefore undesirable in many applications. To prevent efflorescence, materials can be coated or treated to protect their surface.