We know that Inquisitors can see based on trace metals in non-metal objects, but can they push or pull on them? I can't remember, did the Lord Ruler pull on Vin's trace metals during their fight? The trace metals in obsidian are probably also difficult to pull/push on.
I think, during the fight, two things happened that shed some light on this:
1) TLR pushed on the metals inside Vin's body. This took a *lot* of strength.
2) TLR managed to push the *glass on the floor*, but barely.
Thus we know TLR could push on the metals in generic glass. He could probably also push on the metals in obsidian. However I don't think there is any indicator that this a matter of anything besides TLR having crazy-strong allomantic strength, and I doubt we've seen any other character strong enough to duplicate the feat. In general it seems likely that obsidian is not unusually responsive to allomancy.
It was, albeit indirectly, created by TLR. You don't think the taint of magic can leave a footprint?
No, we generally do not. The magic in this world follows specific rules. We don't know all of them, but every last one that we have seen, every last one that has ever been found, *including the examples listed above* all involve metals, and only metals. Not only that, but trace metals play only the smallest part in the system and seem very unlikely to get involved unless crazy-strong allomancers get involved. Even if they do, it will still be the metal that is special.
In addition, none of these powers leave "footprints" in the usual sense of the word. Once pushing or pulling (physical or emotional) is done, the item (person) moves on its new trajectory following the "non-magical" laws of physics; it has been changed, but the change does not continue; there is no allomantic radiation given off, or any continuing magical change. I've heard rumors that internal pushing and pulling might leave permanent scars, but that's probably more like bending metal with a pull and leaving it be; there is no trace of pulling left over after, just the bent metal (or person).
What you don't seem to understand is that we don't expect EUOL to change the rules midstream. We expect the final picture to make sense in terms consistent with what we already know. You could keep saying things along the lines of "Prove that obsidian can't have magic powers!" and we won't have a final answer for you until we actually read the last book. That doesn't mean that our answers aren't sufficient; we logically cannot prove a negative. We just have to give reasons to think the negative is unfruitful and why we choose to ignore it. Your protests to the contrary aren't swaying anybody; they're just ticking us off, largely because they aren't really adding anything to the debate.
