moritheil said:
I'm with you up to the point where you cite the aura as your reason - Nystul's Magic Aura grants an aura but doesn't make an object magical . . .
The aura is merely an indication. In any case, the fact that it is possible to form an illusionary aura (note that spell itself says "the aura is false") doesn't mean much. In general, magic items have a magic aura, and non-magic item do not. Further, the name of spells such as "Magic Weapon" do give a hint as to their effect: they make a weapon magical. I'm not trying to suggest that an aura is the cause of an items immunity, but it's a good indication. In any case, there's a good case to be made that permanent magic weapons don't have the same aura as weapons affected by
Magic Weapon, so it certainly can't be said that a particular aura is somehow a prerequisite for immunity from
Shatter - it's just an indication.
Even if the aura were identical, it's perfectly possible to nevertheless distinguish between "true" magic items and items with a spell cast on them, but it's not really necessary: if a weapon is under the spell "magic weapon", and can bypass damage reduction/magic, and has the telltale increased hardness and hitpoints of a weapon with a magical enhancement bonus; and if the game mechanics make no difference between the effect of a spell or the effect of a permanent enhancement, then it stands to reason that it's not in any way implied that there is a difference in
effect at all - there isn't a single instance of such a difference I can think of.
Of course, while there's no difference in
effect there is a difference in
cause. That's important, since it's possible to affect the cause directly, and spells which do this - such as dispel magic, and potentially detect magic - do distinguish between two otherwise identical effects. Then, with respect to
Shatter: where's the cause/effect hierarchy here? Is an item immune from
Shatter because of the effect (some cause has turned the item magical, and we care only about the effect that it's magical)? Or, is an item immune from
Shatter because of the cause (some magical cause has effected a change, and we're only interested in the cause, which must be that it's inherently a magic item)? Since the game only distinguishes between causes in the most straightforward and explicit cases, and otherwise treats identical effects identically, it's my preference to do the same for
Shatter: No matter the reason that the item is magical, if it is, then it's not affected by
Shatter.
So the effect of targeting a fingernail with Shatter is the same as targeting the whole creature.
