No, you can only find them in the underground. It's not incredibly difficult, just may be time consuming.
You can find stones undergrounds.
A few stones can be found elsewhere but majority is underground ( NO TRADE STONES )
There are two ways to evelove Pokemon in Pokemon platinum by lefstones and leveling up.
buy the Pokemon platinum book
You cannot buy dynamite in the pokemart's of Pokemon platinum .
The Underground
there is none sorry
Iron Island.
there is this guy in the sea at sunyshore city then you talk to him and he changes all the shards into stones or you can buy the NDS action replay ultimate code for Pokemon and get 999x stones of every kind
Togetic into Togekiss and Roselia into Roserade
You can not get PP ups in Pokemon platinum.
You can find stones Underground. You take the explorer kit and then go underground.