Patina

The Dresden Frauenkirche. The church was destroyed during the bombing of Dresden in 1945 and then rebuilt from 1993 to 2005 with new material; the stones with the black patina are the parts that survived the firebombing from the original 18th-century church.

Patina (/pəˈtiːnə/ pə-TEE-nə or /ˈpætɪnə/ PAT-ih-nə) is a thin layer that variously forms on the surface of copper, brass, bronze, and similar metals and metal alloys (tarnish produced by oxidation or other chemical processes), or certain stones^[1] and wooden furniture (sheen produced by age, wear, and polishing), or any similar acquired change of a surface through age and exposure.

Additionally, the term is used to describe the aging of high-quality leather. The patinas on leather goods are unique to the type of leather, frequency of use, and exposure.

Patinas can provide a protective covering to materials that would otherwise be damaged by corrosion or weathering. They may also be aesthetically appealing.

^ Vazquez-Calvo, C.; de Buergo, M. Alvarez; Fort, R. (2007). "Overview of recent knowledge of patinas on stone monuments: the Spanish experience". In Přikryl, Richard; Smith, Bernard J. (eds.). Building Stone Decay: From Diagnosis to Conservation. European Geosciences Union; General Assembly; Geological Society of London. pp. 295–307. ISBN 978-1-86239-218-2. Retrieved 26 September 2012.

[AssemblyPřikryl2007-1] Vazquez-Calvo, C.; de Buergo, M. Alvarez; Fort, R. (2007). "Overview of recent knowledge of patinas on stone monuments: the Spanish experience". In Přikryl, Richard; Smith, Bernard J. (eds.). Building Stone Decay: From Diagnosis to Conservation. European Geosciences Union; General Assembly; Geological Society of London. pp. 295–307. ISBN 978-1-86239-218-2. Retrieved 26 September 2012.

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