You can buy several at the Pokeathelon Dome, there is a girl that gives you one if you have her number and others are either given to you or just found.
all the stones are in the pokethon
witch Pokemon evolve with stones in soul silver
you smell
win a bug-caching contest
You can get fire stones at the pokeathlon. You exchange your points for them. Hope this helps!
You use HM Rock Smash on smashable rocks.
You can find stones in Pokemon SoulSilver by looking around in caves, rocks, etc. Sometimes people might give them to you.
gravler might be holding it but that's all i know
You can win them at the bug catching contest but only if you get first place. You can also buy them at the pokéathalon
you can't get underground in soul silver. if you're looking for stones trade Pokemon from diamond, pearl, or platinum holding them.
After you complete the National Dex, you can get Shiny Stones on: Mondays, Wednesdays, Thursdays, Saturdays, and Sundays.
in soul silver