You can find them in the underground.
to get a leafeon in Pokemon platinum, you need to have an eevee and then at any lvl you have to use a leaf stone!
You got to go to iron island and at the end of it you find it
To find a shiny stone in platinum you have to dig in the underground tunnel.
in Pokemon diamond ,pearl ,and platinum you find them underground other Pokemon games you are most likely to find them on the ground in small poke balls
u get a leaf stone at the old ruins.if u keep lookin in there maybe youll find one -Sset the Pokemon genios(yes I am a girl)
Dusk Stones cannot be found in any GBA game. Stones like this are exclusive to Diamond, Pearl, and Platinum. Likewise you can't find a dawn stone or shiny stone in any GBA game.
The fastest way is to earn points on the Pokemon-a-thon and buy a Leaf Stone there for 2500 points. The Leaf Stone is available at Thursdays I think. You can also get a leaf stone from Bill's Grandpa if you show him an oddish, he is just above Cerulean city. and you can find a leaf stone in viridian forest.
You need to catch an oddish or a gloom and then make oddish evolve into gloom at lv.21 then use a leaf stone on it. Hope I helped
To get Pokemon number 71, just find weepinbell at route 224 or 230 after you've obtained a National Dex and evolve it with a leaf stone.
on route 225 there will be a dawn stone
in the underground
You can find them in the Underground.