dig it up in the underground or Oreburgh Gate, in the basement, you can use a combination of Rock Smash, Surf, and Strength to reach it.
there is no such thing as a "Curse Plate."
there is no such thing as a curse type
its the rarest thing in the underground also it behind the Pokemon statue in Eterna City
Heatran is a ledgendary in Pokemon platinum.
There is not a route 233 on Pokemon platinum.
You can search on youtube. that's where i found mine.search Pokemon PLatinum plate locations.
It is the earth plate you can get it at the oreburgh gate or at the underground.
there is no such thing as a "Curse Plate."
Underground!
Arceus (With Dragon plate)
The ground or Earth plate is in Mt. Coronet on the west side of Oreburgh City. It's downstairs and you need HM Surf to reach it.
you can get iron plate by using explorer kit
a fist plate
purple
you have to dig it up when you are underground
if a Pokemon holds a plate (arceus) and a Pokemon uses flail the shards restore the plate because flail breaks the plate.
no there is no such thing as the polychromatic plate