The 1866 Proof Three Cent Nickel comes from a low mintage of just 725 coins with most pieces surviving. Common up to the gem level in which PR65 and PR66 are scarce and PR67 is rare with just a handful existing. Attractive color and strong strikes can be located with some effort. Cameos bring a minor, gradual premium with the increase in rarity and desirability coming from the deep cameos.