Jewel piece

A jewel piece, also referred to as a Gem Piece,  is a collectable object in Wario Land 4. Four jewel pieces can be found in each level inside a jewel piece box, with a Gold Coin worth 500 points. The boxes have an image of the Golden Diva on the front. When four jewel pieces are joined together, it creates a complete jewel. The player does not need to find all the jewel pieces to go on to the next level, but they do need to find them all in order to battle the boss found at the end of the passage.

The jewel pieces collected in a level can be viewed on the pause screen by pressing. Once the player finds a jewel piece and completes the level, that jewel piece cannot be collected again. However, the box can still be opened to collect the Gold Coin. The location of the jewel piece box varies depending on the game mode the player has selected.

The color of the jewel piece depends on the passage Wario is in.
 * Emerald Passage – emerald jewel piece
 * Ruby Passage – ruby jewel piece
 * Topaz Passage – topaz jewel piece
 * Sapphire Passage – sapphire jewel piece

Four purple jewel pieces appear in Hall of Hieroglyphs, and four golden jewel pieces appear in the Golden Passage.

When Wario Land 4 was in development, Wario originally needed a key to unlock the four boxes (much like in Wario Land 3) to gain the four jewel pieces. In the final game, Wario merely has to touch the box in order to open it. Besides the Keyzer, no other type of key is seen in the game.