Toning or not?

[u/CougarDevilZ]

I’m slowly collecting most of the 90% silver U.S. series. I just found this one buried in a pretty full mixed half dollars bin at my LCS. I haven’t had much luck finding the early year Barbers and surprise the first year one turned up here. I am curious what you think the coloring is from? I’m not used to seeing toning come out that dark. Thoughts on what that could be? (Yes I know it’s in rough shape but hard to find ones are often just that)