This was just a fun project while I was learning about forming. It was a disc of copper hammered into a dome. Then I flipped it over and hammered the dimple in. Lot's o' enamel. That is what gives the depth of colour to the orange, it is built up from a bunch of different opaque and transparent enamels. Sort of like french cooking, building on variations.
looks sort of like 1967 to me. But then again, I was born in '70, so what do I know.