answers: Verdigris
context: Green rust Green rust is a generic name for various green crystalline chemical compounds containing iron(II) and iron(III) cations, the hydroxide () anion, and another anion such as carbonate (), chloride (), or sulfate (), in a layered double hydroxide structure. The most studied varieties are Other varieties reported in the literature are bromide , fluoride , iodide , nitrate , and selenate. Green rust was first recognized as a corrosion crust on iron and steel surfaces. It occurs in nature as the mineral fougerite. The crystal structure of green rust can be understood as the result of inserting the </s> from Latin "virescere", "to become green". In the English language the term virescent may also refer to greenness (cf. verdant). Virescence Virescence is the abnormal development of green pigmentation in plant parts that are not normally green, like shoots or flowers (in which case it is known as floral virescence). Virescence is closely associated with phyllody (the abnormal development of flower parts into leaves) and witch's broom (the abnormal growth of a dense mass of shoots from a single point). They are often symptoms of the same disease affecting the plants, typically those caused by phytoplasmas. The term chloranthy is </s> Verdigris Verdigris is the common name for a green pigment obtained through the application of acetic acid to copper plates or the natural patina formed when copper, brass or bronze is weathered and exposed to air or seawater over a period of time. It is usually a basic copper carbonate, but near the sea will be a basic copper chloride. If acetic acid is present at the time of weathering, it may consist of copper(II) acetate. The name "verdigris" comes from the Middle English "vertegrez", from the Old French "verte grez", an alteration of "vert-de-Grèce" ("green of Greece"). The modern
question: what 's it called when copper turns green