Patina vs. Verdigris vs. Rust

I thought today "What is the difference between patina and verdigris?" and "Why don't we just call it rust?" Patina is my descriptor of choice, but I very well know what verdigris means, I just have no need to use it myself.

PATINA: Italian, from Latin, plate (from the incrustation on ancient metal plates and dishes)

1. A thin greenish layer, usually basic copper sulfate, that forms on copper or copper alloys, such as bronze, as a result of corrosion.
2. The sheen on any surface, produced by age and use.
3. A change in appearance produced by long-standing behavior, practice, or use: a face etched with a patina of fine lines and tiny wrinkles.

VERDIGRIS: Middle English vertegrez, from Old French verte grez, alteration of vert-de-Grice : verd, green; of + Grice, Greece (roughly translated that is: Green-of-Greece; Grecian Green)

1. A blue or green powder consisting of basic cupric acetate used as a paint pigment and fungicide.
2. A green patina or crust of copper sulfate or copper chloride formed on copper, brass, and bronze exposed to air or seawater for long periods of time.

RUST: Middle English, from Old English rust; from reudh- (redness) in Indo-European roots

1. Any of various powdery or scaly reddish-brown or reddish-yellow hydrated ferric oxides formed on iron and iron-containing materials by low-temperature oxidation in the presence of water.
2. Any of various metallic coatings, especially oxides, formed by corrosion.


So it seems that I would be slightly more correct refering to the green oxidation of church spires as verdigris rather than patina.

In Summary:
Patina = the actual plating or coating of the copper sulphate,
Verdigris = the greenish colour originating from something copper,
Rust = red, ferric oxide