You need to use the move Rock Smash which you get in Mauvile City.
HM06 Rock Smash
You can break rocks by using the move Rock Smash.
get the HM strength, and teach it to a Pokemon
There is no TM that can Break rocks in Pokemon leaf green there is however in HM that breaks rocks called RockSmash
If you're talking about the small, rugged rocks, then I don't think you can. The only rocks I know you CAN move/break are the huge boulders made for Strength.
HM06 Rock Smash
there is a labrynth of islands and rocks that you need to progress through to get to regiice. this maze begins toward the south west of rustboro city.
Strength is given to your character after you use rock smash on the rocks in the cave to the left of Rustboro and above Verdanturf. The guy will get all happy ang give you it. Romance, ew.
break verdanttuff's rocks, i think.
press a on the rocks
strength
You can break rocks by using the move Rock Smash.
There are an infinite amount of shards that you can get from wild Pokemon and limited ones you can find under the sea in rocks or above in rocks.
get the HM strength, and teach it to a Pokemon
There is no TM that can Break rocks in Pokemon leaf green there is however in HM that breaks rocks called RockSmash
Granite cave use rock smash on rocks in the cave and he will come out. it is on dewford
You go to Mauville City and talk to the Rock Smash Guy.