While the rules for the Aetherkineticist's blast state that the projectile's material doesn't influence how it interacts with DR /Regeneration, does the same apply afterwards?
In other words...if an Aetherkineticist flings a chunk of Viridium at a human, and the damage to the Viridium will shatter it, what would the effect be on said human? What about a cold iron chunk to a fey, or silver chunk to a werewolf? (Please note I'm asking about aftereffects of a chunk of material exploding into shrapnel on its way through a target that has a certain vulnerability to that material. I know the DR will affect the initial hit, but what happens afterwards?)
Nothing happens. If your GM wants to Rule of Cool something like that, they can. For anything where you'd like the material to be relevant, use the "throw" option. You're not embedding anything in them, nor is there any indication that it explodes into shrapnel when/if it breaks.
If something takes effect upon breaking, that's potentially going to be relevant, though.