I separate the spiral (snake) more distinctly than that.
The white (or, more usually, colored) snake is not very much inside the trans. glass. What shows as white on an Onyx (always white, never colored) is a wider cork that can nearly fill the marble - but it never completely does.
If it did, it would be an Auger.
Looked at from the pole, if the pole is open, it`s an Onyx. If it`s closed, it`s an Auger.