I distinguish between splits, which by my definition are open, and cracks, which are mostly closed. Of course there are a lot that are a
bit of both. I would call yours a
crack, not a split.
For me, cracks are a minor flaw. Of course if they are very ugly, detract from the
types or important legends, or are so long the coin looks like it will break they can be a major flaw.
A small closed
crack like yours will have very little impact on my
price. Some, but very little.
Some
types are almost always cracked or split and authenticity must be examined more closely if they are not.