The image is a bit fuzzy and hard to see details, but maybe this coin sat 'heads up' in a caustic or acidic environment.
Collecting since 1972. Learning from then on
"Tell me and I forget. Teach me and I remember. Involve me and I learn." - Benjamin Franklin
My Dansco 7070 type set coin count: 45/76 My American Silver Eagle Collection - 1986 to Present My Dansco 8188,8189 Innovation Dollar Albums My Dansco 8176 Eisenhower-Dollar Album My Dansco 8166,8167 Kennedy-Half Dollar Albums
My Dansco 8140,8143-8147 Washington-Quarter Albums My Dansco 8125 Roosevelt-Dime Album My Dansco 7112 Buffalo-Nickel Album My Dansco 8113,8114 Jefferson-Nickel Albums My Dansco 8100,8104 Lincoln-Cent Albums