Efflorescence, a white, powdery substance appearing on building materials, is a result of dissolved salts reaching the surface and crystallizing. While unsightly, it typically does not harm the structural integrity of concrete, brick, or stone. However, in severe cases, it can lead to erosion, flaking, and spalling of the surface. Prevention measures like proper drainage and efflorescence-resistant materials are crucial, while treatment involves cleaning the surface and addressing moisture issues. Professional masons and industry organizations provide guidance on best practices for managing efflorescence.