Does it look or feel like balsa? I'm not sure but then it's hard to tell in the pic.
Balsa wood stops are sometimes used to fine tune straight edge razors. When you strop on leather, the edge can be progressively rounded. This slowly changes your blade from a V shape to a very sharp U shape. After a few weeks or months, leather stropping might not be as effective. When this happens, stropping on the balsa wood strop will usually return the razor to shave readiness.
I'm not sure this is what you have. Just a guess.