Imagine you are chopping the log with an axe. You chopped it into parts, and every part has some outer surface, been previously the outer part of the log [bark], and newer surfaces, been previously the inner part of the log, now split from each other, and splintered.
How do you call the latter? One of this inner surfaces, more light on the picture.
A Chip is defined by Merriam-Webster as
a small usually thin and flat piece (as of wood or stone) cut, struck, or flaked off Blockquote
while the inner surface seems to be pretty big compared to that.
Crack and split seem not to be done completely, as if log is not broken yet.
Splinter seems to be something like shard, and also very small.
And the cleavage is (M-W)
a fragment (as of a diamond) obtained by splitting
but also
the action of cleaving or splitting : the state of being cleft
which I am not sure what to think about.
