The Armor Fossil and Skull Fossil are game-specific, meaning one can be found in one game while the other can't. The Armor Fossil can only be found in Pokémon Pearl and the Skull Fossil in Diamond. There are an unlimited amount of Armor Fossils Underground for Pearl players and can be traded without having to trade your only one. After unlocking the National Dex, players can also find the Root Fossil, Claw Fossil, Dome Fossil, Helix Fossil and the Old Amber by digging in The Underground.
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