Cinnabar or Cinnabarely?

I’ve never really learned how to properly ID cinnabar. I can tell something isn’t cinnabar sometimes on bad modern repros. I believe its production is achieved by applying layer after layer of material until you get a desired thickness. I have an exposed edge here which should be a good lesson on what it does and does not look like. I don’t see layers but I’m not sure you’d actually be able to see them on a cross cut. I’m assuming this is NOT cinnabar. We all know about assuming though. Can anyone confirm this is not cinnabar? Looks like a hardened foam kind of. Not sure what it actually is. Doesn’t strike me as resin but it surely could be.