The online etymology dictionary suggests:
"case for holding arrows," 1322, from Anglo-Fr. quiveir, O.Fr. quivre, probably from P.Gmc. *kukur "container" (cf. O.H.G. kohhari, O.Fris. koker, O.E. cocur "quiver"); said to be from the language of the Huns.
link
here.
Nothing about copper, I'm afraid. Interesting to think we might still be using a word derived from Hunnish, correctly... Weren't they reputed pretty good horse archers?
Oh, and a good dictionary link:
onelook dictionaries
It searches a shedload of online dictionaries for you...