I have read that Ghost wood is Oak Root sections. It stands to reason that it is some sort of hard wood. It lasts and lasts in the tank and incidentals like certain mosses will grow and root onto it. I have regular Oak with the bark on, and incidentals such as fungi(mushrooms)seem to start easier on the ones with the bark on. I have had mushrooms come up on ghost wood without bark but I think it was more from decomposing plant on the wood. I vote for Ghost wood, and yeah, its costly, but I think its worth it, no other woods have looked as pretty just all by itself, and seems to bring the tank to life even without too many plants. Perhaps using a few pieces just as focal point would be more cost effective.