on a deck in the main city
black stone
You can find a Shiny Stone in route 6.
go underground and keep digging till u find a water stone or a fire stone
The Black Stone is on display at Nacrene City's museum.
For starters in Driftveil you can get one near the lighthouse. You may be able to find one (rare) in caves
find them
No such thing.
The water stone is found in the Solaceon Ruins. Go into all the chambers with a rock in the middle of them. You will find a Water stone. Also, in the Solaceon ruins, you can also find a Thunder stone and a Fire stone.
You can find a Water Stone on Wednesdays in the Pokeathlon Athlete Shop for 2500 points.
In Pokémon Black, you can receive a Water Stone from a person in Castelia City provided your answer to his question is Panpour. Additionally you can find Water Stones within Dust Clouds that appear in Driftveil City, Wellspring Cave, Mistralton Cave, Chargestone Cave, Challenger's Cave, Giant Chasm, Twist Mount and the Victory Road.
the bays at castelia city
You can evolve panpour into simipour.