Hello everyone.

So this is one of many questions I have regarding bending, but this one came up recently. By the canon standards and by your own opinions, what counts as "earth" that can be bent?

It's easy to see that rocks, soil and sand count. Also, metal apparently counts but only because it's not truly pure. What about porcelain? What about concrete? How about rotten wood? I mean, most of soil is made of dead trees, corpses and feces, but I don't imagine earthbenders to be able to move any of those things on individually or fresh. We know from canon that wood doesn't count.

I'm interested in creating a kind of guideline that's sufficiently intuitive so that I don't have to get all lawyery with my earthbending PCs and that also makes sense with the story.