It’s a copper coated zinc cent. Someone removed the copper on the reverse by grinding down the design. In other words, it’s damaged.
More info: the obverse has a rim, which means the coin was “upset” properly (in the Upsetting Mill) which creates the rims on both sides. Yet, the reverse design and rim are gone, probably from sliding on fine grit sandpaper or using a dremel-type grinder. The copper plating on the CPZ is only about 7 microns thick. The before-grinding weight would need to be known to find out how much the weight of the coin was diminished, both plating and some of the zinc core having been removed.
