buy it in celdon city
Exchange Blue Shard with the Waterstone. You'll find waterstone in Abandoned Ship, too.
Poke'athalon
For which game? Pokemon Red Pokemon Blue Pokemon Yellow Pokemon Gold Pokemon Silver Pokemon Crystal Pokemon Sapphire Pokemon Ruby Pokemon FireRed Pokemon LeafGreen Pokemon Emerald Pokemon Diamond Pokemon Pearl
only vapreon
lombre and staryu.
I know poliwhirl will evolve to poliwrath and that shelder will evole to cloyster with the waterstone
You can buy one with Athlete Points at the Pokeathlon Store on some days, or you can get a Waterstone from Bill's grandfather after you show him a certain Pokemon.
Dig it out in the underground.
Its evolve to Vaporeon from eevee
You Need A Waterstone.
You can buy them at Celedon's Department Store.
Yes, you can dig up a waterstone in Pokemon platinum underneath the resort area.