Fossil
From Wild World Wiki
Fossils are relics of times gone past. Three fossils appear in your town every day, however they must be dug up to access them. You can tell where a fossil (or other item) is buried by the star-shaped crack in the ground it is buried in. When you first pull a fossil from the ground, it is a round blue object. This is the standard fossil, and cannot be sold (though Nook will take it off your hands if you wish).
Take this fossil to Blathers and he will appraise it for you. When appraised, the fossil's true form will be revealed. Blathers may ask to keep the fossil for the Museum if it is the first of it's kind to be shown, however you can request that you keep it. Identified fossils are highly valuable, and can sell for several thousand bells. They can also be used as furniture in your house.
