I forgot about the dusk stone,but I think u need to go underground to find the sun stone.
a dusk stone evolves dark types sun stone evolves grass types and moon stones evolve normal types
The evolution stones in Diamond/Pearl/Platinum are the water stone, fire stone, thunder stone, moon stone, leaf stone, sun stone, dusk stone, shiny stone, and dawn stone. (Sorry if I missed one) And even though this is the opposite answer, the stone to keep Pokemon from evolving (with or without evolution stones) is the everstone. Hope this helps! :)
underground
You can evolve Sunkern or Gloom with a sun stone. Gloom to Bellossom. Sunkern to Sunflora.
There are many stones in pokemon, and many stones have the same rarity. In my opinion, the rarest stone is either the sun or dusk stone.
Thunder stones, Water stones, Fire stones, Leaf stones, Shiny stones, Dusk stones, Oval stones, Moon stones, Sun stones.
in order to evolve Roselia you have to use a sun stone on it You use a shiny stone, not a sun stone.
You find sun stone underground!
you get the national pokedex then find it underground
to get bellossom in Pokemon pearl, first get a gloom. then use a sun stone on glooom and it will evolve to belossom.
gloom to bellosom sunkurn to sunflora Sunkern and Gloom are the ones who evolve using a Sun Stone.
Here are SOME stones: dawn dusk leaf fire sun water oval stone everstone (prevents Pokemon from evolving) moon thunder these are all of the stones i know about.