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Jewels are collectibles in Wario Land 4. Each one is made up of four Jewel Pieces, joined together. Each Jewel Piece is found in a Jewel Piece Box, four in each level. Wario must collect these to proceed in the game, because at the end of each Passage, there is a Boss Door where the jewels fit. When all jewels in a Passage are recovered, Wario gains access to the boss of that Passage. Each Passage has different colored Jewel Pieces to collect:
Jewels also appear in Densetsu no Starfy 3. Wario collects four blue ones with Starfy in Undersea Ruins but Kyorozo takes them away in Undersea Ruins' level 4 so Starfy and Wario have to retrieve them. They are used to open up the door in level 4 leading to the area's boss — Gachatakkoru.
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