Rough Gems are an Item used to build the fifth Masterpiece, the Jeweled Triceratops Masterpiece, in Rank 4. They can also be used to build a Seal of the P.O.S.. Rough Gems are obtained by receiving them randomly in a message from a friend's Dino Bone Gallery Module, Dino Bone Sticker Module, or Dinosaur Excavation Module. There are three different types of gems that can be received via mail: 10 of each are needed for the Jeweled Triceratops Masterpiece and 5 of each are needed for the Seal of the P.O.S. This is why Rank 4 takes a long time and is a lot harder to complete than previous ranks.