The Smooth Rock, first appearing in Pokémon Diamond, Pearl, and Platinum games, is a hold item that extends the duration of the move Sandstorm, which normally last for only five turns, so it lasts for eight turns instead. (A 60% increase in time).
 In-Game Descriptions
- Diamond/Pearl/Platinum: A Pokémon hold item that extends the duration of the move Sandstorm used by the holder.
- HeartGold/SoulSilver: A Pokémon hold item that extends the duration of the move Sandstorm used by the holder.
- Black/White: A Pokémon held item that extends the duration of the move Sandstorm used by the holder.
 How To Obtain
• This item cannot be bought in shops in-game on any generations and game cartridges.
• This item can be traded between Diamond, Pearl, Platinum, HeartGold, SoulSilver, Black, and White games, provided the Pokémon being traded is holding the Smooth Rock as its item and both game cartridges can trade back and forth.
- Diamond/Pearl/Platinum: The Smooth Rock can be obtained from mining it in the Sinnoh Underground.
- HeartGold/SoulSilver: The Smooth Rock can be found on the Icy Mountain Road Pokéwalker Route after taking 3,500 steps and using the Dowsing MCHN.
- Black/White: The Smooth Rock can be obtained from the parasol lady on Route 8 once a day during the evening.
 Strategizing with the Smooth Rock
A good strategy is to send an Ground-type Pokémon holding the Smooth Rock into battle against an effective type matchup, such as Electric, and use Sandstorm as your first move. Then, the opposing Pokémon will suffer damage each turn of the sandstorm, while you'll remain unscathed.