A Shiny Stone is an item that appears in Super Mario RPG: Legend of the Seven Stars.
A Shiny Stone can be used to unlock the locked door in Monstro Town that leads to Culex. In order to get a Shiny Stone, one must head to Moleville and first purchase Fireworks for a pricey 500 coins. Then, they must give the Fireworks to a mole girl who will then give away a Shiny Stone. A Shiny Stone can also be traded for a Carbo Cookie.