How To Find Shiny Stone In Soul Silver?

Go to Route 14 (Kanto Region) Battle everyone there if you didn't already. One of them should have your number they will call you and you will receive a shiny stone.
Also in Pokeathlon for 3000 points. (Unavalaible on Tuesdays and Thurdays.)

Togetic-Togekiss (Shiny Stone)

My team!!! (Just look)

Mew Lvl 98
Mewtwo Lvl 98
Typhlosion Lvl 98
Celebi lvl 86
Lugia lvl 87
Venusaur Lvl 99

I believe you have t have the National Dex before the stones show up in the Pokeathlon Dome.

You can get one by getting Suron Points in Pokéathlon and exchange 3000P for a Shiny Stone, but they are not available on Tuesdays or Fridays.
There are other ways to get one too, I believe that you can receieve one as a prize in Bug Catching contest.

I can't see shiny stone or water stone which are the stones that I want anywhere in the pokeathlon dome where do you find them