Thunderstone while casting

[tchrman35]

Scenario:

character 1 requires an action to throw a thunderstone if character 2 starts casting.

Character 2 casts a spell, so character 21throws the stone.

Character 2 must make a fortitude save vs deafness (dc15).

Is character 2 subject to a dc [thunderstone]15 + spell level concentration check to keep from losing the spell on account of the really loud bang that just happened?

It would seem like it should to me, but I'm not sure by RAW.

[David knott 242]

By RAW, the thunderstone is neither a source of damage nor a distracting spell, so there seems to be no way for it to force a concentration check. However, if character 2 failed the save vs. deafness, he has a 20% chance of spell failure from the deafened condition, assuming that the spell he was casting has a verbal component.

[Crimeo]

Nope. Thunderstone IS an attack, but concentration doesn't list a save for just any attack. Only for damage sustained, or for SPELLS that affect the caster during casting. (or some other stuff that doesn't apply)

Totally silly, since if it were a spell that had precisely the same effect, instead of an alchemical device, it would cause a check. So I would definitely house rule this to count. But by RAW, no.