One-leaf clover necklace was removed from RuneScape after an update, but still exists in-game for those who had obtained it.
The one-leaf clover necklace was an uncommon item found from using the other three clover necklaces won on the Squeal of Fortune. When worn, it grants a +5 boost to a random skill for 30 minutes. The item has infinite charges but may only be activated once daily. If the boosted skill falls below the boosted level, it returns to the boosted level shortly after.