This is an experimental piece, in copper, using a lettered edge collar containing the words "E Pluribus Unum".
Only 3 examples are known, all defaced with chisel marks, and all 3 show some lettering on the edge.
1) Taylor-Windle (H Chapman 6/08) lot 1289?,
Connecticut State Library, ex Mitchelson
2) Woodin, Newcomer, Boyd, Farouk, Judd, 66 ANA, Coronet Coin FPL (Krouner), Merkin 2/71, Queller-Heritage 4/09, Heritage 8/11 ANA, Heritage 8/16 ANA - NCSXF40, cleaned, illustrated above
3) Lohr, Cox, RARCOA 4/72, 74 FUN, Heritage 2/83, Stacks 5/85, Queller-Heritage 1/09 - NGC60RB illustrated below.
Photos courtesy of Heritage.