They can be sold at kecleon shops in dungeons
I think you need a thunder stone to evolve pikachu hope this helps you
You have to have a water stone.
Get A Thunder Stone! And Then Go Evolve it!
you need a pichu and the wonder mail code you can get them off Pokemon websites
the Pokemon that evolve with the help of a thunder stone are : pikachu +thunder stone = raichu, or eevee + thunder stone = jolteon.
a shiny stone isn't in this game but i believe it's in explorers of time,,darkness, & sky.
In Pokemon Mystery Dungeon: Explorers of Darkness, you can receive a Shiny Stone as a reward for completing certain missions or by finding it in certain dungeons. You can also sometimes receive a Shiny Stone as a gift from other Pokemon in the game.
you need a wondermail mission to get it that's the only way ;D
In Pokemon Mystery Dungeon: Explorers of Darkness, you can find a Thunderstone by exploring floors in dungeons, purchasing it from Kecleon Shops, or as a reward after completing certain missions. It can also be obtained as a reward from Pelipper Post Office missions.
usually,in a dungeon if you find a kelcleon shop.Or you could trade from Pokemon ex of time/darkness.
thunder Pokemon if it has evolutions
You can find the thunder stone in New Mauville