i tried to get a shiny stone to evolve my roselia LV.67 but i cant find the stone and i have picked up every single pokeball shaped item that i can find and i keep on getting shards and pokeballs and nothing else.and i am bursting for a roserade!!!
There are FOUR in the game:
Iron Island- In the last room.
Route 210- In the Northern (foggy) Section, South of the pit between the climbable rocks (requires Rock Climb) (hidden).
Route 228- At the end of a narrow bridge south of the pair of Pokémon Rangers
Ability "Pickup"- Click here for a table on how likely you can get aone and at what level.
Source: Bulbapedia/ Shiny Stone
You can find a shiny stone in Platium here: Route 228, Route 210, Iron Island, Pickup Ability
Hope I Helped :D