There are various evolution stones that you may need. Here are some of the more commonly asked for Stone locations.
You find the Dusk Stone in Cerulean Cave in the green crystals to the left of MewTwo
You can find the Dawn Stone near the summit of Mt. Silver between two trees, inside of a pokeball.
You can find the Shiny Stone by entering National Park, and heading straight to the northen most point, and head up the stairs behind the railings.
Celedon & Goldenrod Department Stores sell Evolution Stones on the 4th floor. Here are the stones sold, and alternate (free) locations you can find them, as we know them:
- Fire Stone
- Leaf Stone
- Water Stone
- Thunder Stone (Also found as an Item in the Power Plant)
Mega Stones are coded into the game, but are not currently obtainable.