From 1793 to 1837, this was pure copper; in 1982 its composition was changed to 97.5% zinc & 2.5% copper
... (Except that in 1943 only, the 
coin's composition was changed to zinc-coated steel due to the ... 1982, when the 
composition became 97.5% zinc and 2.5% copper (copper-plated zinc) ... quarter 
at a cost well below their face values, the significantly higher... [DOC] [TLE] Summary of lesson [PAR] Zinc coated steel; pure copper in a few.