"Welcome to alchemy!" Harry laughed. "It's all a bit like that, all allegory and subtext. The Stone is a stone ... but not a stone. It is burned down to a powder, but also used as a liquid solution and a gas. It all makes sense when you get used to it. For now, all you need to know is that we must treat my base matter in a White Elixir solution ... and then try to purify it one stage further.