"Over the course of many years, Mako energy crystallizes into Materia..."
The Materia Caves are special locations in Final Fantasy VII scattered across the World Map only accessible by a special chocobo, with the exception of the Quadra Magic through the Quadra Magic Cave Glitch. Inside each cave is one special Materia not available anywhere else. The Materia have an appearance unique from the other Materia and emit great amounts of light.
The four Materia are:
Mime: Gives the Mimic command that copies the last attack the party performed; located on Wutai island. Accessed by green chocobo (2nd generation).
Quadra Magic: Allows the paired Materia to be cast four times in a row, albeit with reduced power; located north of Mideel. Accessed by blue chocobo (2nd generation).
HP<->MP: Switches the character's HP and MP max; located in the Materia Cave across the river from the entrance to Mt. Corel. Accessed by black chocobo (3rd generation).
The Materia Cave on the continent of Wutai is mentioned in a Case of Yuffie. After the events of Meteorfall, the Lifestream summoned from the Planet had changed the geology of the area and the cave could be visited on foot.
Yuffie Kisaragi and Yuri travel toward the cave when looking for a cure to Geostigma, hoping for a Materia that could cure the disease. The cave does not get visited in the end, however the two visit a cave formed by the geological changes nearby suspecting the Lifestream may have moved the Materia to the cave.
The Mime cave is accessible by a green chocobo.
The Mime cave.
The Quadra Magic cave is accessible by a blue chocobo.
The Quadra Magic cave.
The HP<->MP cave is accessible by a black chocobo.
HP<-->MP cave.
The Knights of the Round is accessible by a gold chocobo.
The Knights of the Round cave.
