you can dig it up from underground. it will have yellow shards coming out from a dirt-ball looking rock. also i think you mean smooth rock.
Chat with our AI personalities
To find a shiny stone in platinum you have to dig in the underground tunnel.
on route 225 there will be a dawn stone
you can find a thunder stone by checking the UNDERGROUND
When you mine regular 'smooth' stone, you get cobblestone. This can be converted back to smooth stone by smelting it in a furnace.
you can probably get it Underground.