Rarely, Wondrous Fossil Rocks can appear in the Fossil Guild for a sale price of 50,000 G.
You find them in great quantities at the Pay-to-Dig site at Treasure Lake. You can get some in the sidequest at Hot Springs where you cook eggs, one for the Dropping fossils quests, one for Concentrate, a few from the storyline, and you can find them in any dig site (Ryne mask boosts the chance of these fossils appearing) .
Wondrous Fossil Rock Stat Boosts
|FOSSIL||ATTACK BOOST||DEFENSE BOOST||ACCURACY BOOST||SPEED BOOST|