"a copper shone the pot" is incorrect. "shone" functions as a verb in that sentence which makes "a copper" the subject, "shone", a transitive verb, and "the pot" its object; i.e., the copper did something to the pot. It *shone it. "shone" isn't a transitive verb. We're looking for an adjective; i.e., Japanese, dou-ka iro (?), copper (in) color. The pot is copper in colour.
With or without a dash works:
EX: copper coloured
I'd go without the dash; "copper coloured pot" isn't ambiguous.