You can get the thunder stone by going underground and digging for it in Pokemon diamond/pearl ( the thunder stone , fire stone, water stone, and the leaf stone is very rare, so good luck!).
You can find the thunder stone in New Mauville
you can find a thunder stone by checking the UNDERGROUND
You find the thunder stone in Celadon Mall level 4, wise man gifts.
in the ruins with the unknown
You can find it anywhere.
sunyshore city or the underground
the Pokemon that evolve with the help of a thunder stone are : pikachu +thunder stone = raichu, or eevee + thunder stone = jolteon.
Sunny shore city
Use a thunder stone on an eevee
sunyshore city or the underground
there is no "electric stone" but there is a thunder stone witch can be found under ground
if you dig underground you'll eventually find thunder stone then after a while you'll find shiny stone ;^)