It depends on thew Pokemon. Most Pokemon evolve by gaining exp. Here are some Pokemon that evolve with a stone.
Evee- can evolve into 7 different Pokemon depending on the stone
Lombre- water stone
pikachu- thunder stone
there are many more
OVAL STONES CAN EVOLVE- A HAPPINY TO A CHANSEY THUNDERSTONES- Can EVOLVE A PIKACHU TO A RAICHU DUSK STONES-EVOLVE MISDREAVUS TO MISMAGIUS OR MURKROW TO HONCHCROW
Evolution stones are used to evolve certain Pokemon.
All Pokemon evolve at different levels. However some require items to be held when evolving, evolution stones to be used or a certain happiness level to be reached.
evolve certain Pokemon
Panpour, Pansage and Pansear evolve when evolution stones are used on them.
You go to your bag and select one of the evolution stones you have, then you select "Use" and the screen will go to your Pokemon party. Then you select the Pokemon that is able to use that particular stone to evolve. If you don't have any of the particular Pokemon that uses evolution stones to evolve, it won't work.
you cant buy them but get them underground
you can evolve eevee and gloom
Evolution stones appear randomly, not just in the center of the screen.
Not normally, but they can evolve into their Mega Evolution forms in battle through the use of their respective Mega Stones.
It depends... What Pokemon is it? (Not that I know...)
The water stone is for evolving water Pokemon .If you are a real trainer you will let your Pokmon evolve by level.Only if your Pokemon is a water type and doesn't evolve by trading you could evolve it with a water stone. All stones have the same information by their own type.