It is simply the gathering of pigments at the tip - the pigments you can't see in the quill because they are so sparsely spread throughout it, but where the quill narrows at the tip, those pigments are squeezed together enough for them to be visible. If they have a blue-eye ring, choose medium brown. If they have a blue-grey ring, choose dark brown. It is simply the gathering of pigments at the tip - the pigments you can't see in the quill because they are so sparsely spread throughout it, but where the quill narrows at the tip, those pigments are squeezed together enough for them to be visible. The remainder are white, banded by light grey.
Ears are black and the face is masked.
Skin on the shoulders is jet-black. All other features are the same as Charcoal. Skin on the shoulders is dark grey, almost black. The spines are white, banded with black. The face is white with a black mask, ears and nose.