Artifact

The Artifact is an item found in Dry Dry Ruins in the game Paper Mario. In the area where Mario got the Super Hammer, the Artifact can be found behind a Stone Block. It can be given to Kolorado anytime and giving it to him will earn Mario a Star Piece.

It is never actually specified what kind of item the Artifact is. However, it seems as if it is important to Dry Dry Ruins, as stated by Kolorado when you give it to him.