a thin surface layer that develops on something because of use, age, or chemical action

His tomb was covered with a yellow patina of lichen. 他的墓地上长了一层薄薄的黄色地衣。

something that makes someone or something seem to be something that they are not

Beware their patina of civility, it's only an act. 当心他们礼貌、客气的假象，那只不过是在装样子。

a blue-green layer that forms on copper, brass or bronze