Fire Stone: Celadon Department Store, Mt. Ember
Water Stone: Celadon Department Store, Seafoam Islands
Thunder Stone: Celadon Department Store, Power Plant
Leaf Stone: Celadon Department Store, Safari Zone
Moon Stone: Mt. Moon (×2), Rocket Hideout, Pokémon Mansion, held by wild Clefairy
Sun Stone: Ruin Valley
Source