In terms of being specific, I have only heard ghost used for the marble called an Alley Ghost. It is a semi transpearent marble with ghost like filliments. Blue base and orange swirls. The fillements can vary from leaving clear areas to fully filling the marble and the swirl can vary in browns, oranges to reds.
Having said that I have heard ghost used to describe filliments that float lightly through the marble, wispy and very light. In this case only used to describe a look, but not to decribe a type or specific marble.
Here are some Alley Ghosts....