Patina formation

Patina is a natural surface layer that forms on materials like metal, wood, or stone over time due to exposure to elements such as air, moisture, and pollution. It results from chemical reactions, oxidation, or aging processes, creating a protective or decorative coating. For example, the greenish patina on aged copper, called verdigris, develops as it reacts with environmental elements. Patina can enhance the aesthetic appeal of objects, signaling their age or history, and sometimes helps protect the underlying surface from further damage.