The SpellStones were created by the Krazoa Spirits of Sauria, filled with dark matter that absorb the energy of the planet and hold it together. There are four SpellStones, which actually appear in two variants. A red SpellStone has to be taken to the Volcano Force Point Temple, while blue SpellStones are taken to the Ocean Force Point Temple.
The first of the SpellStones that Fox has to obtain, while rescuing Sauria during Star Fox Adventures, is in the DarkIce Mines, where a large creature named Galdon has ingested it. Fox somehow has to make his way into the belly of the beast and retrieve the first SpellStone, which he then takes to the Volcano Force Point Temple.
The second SpellStone is underneath the CloudRunner Fortress, which is held by a group of SharpClaw on vehicles. Fox has to pursue and crash the SharpClaw to obtain the SpellStone, which has to be taken to the Ocean Force Point Temple.
The third SpellStone is within the Walled City, where the King EarthWalker is held hostage. The city is overrun with RedEyes. Fox has to make his way to the chambers of the Walled City and he has to fight King RedEye, who is guarding the third SpellStone, and take it to the Volcano Force Point Temple.
The last SpellStone is on Dragon Rock. Fox has to free the dinosaurs that are imprisoned and storm the enemy base, after which Drakor attacks. On small flying platform, Fox gives chase to Drakor and defeats it, whereupon it relinquishes the fourth and final SpellStone, and Fox takes it to the Ocean Force Point Temple.
The SpellStones originating areas were in the four satellites they rested on, as implied by General Scale's ultimatum towards Garunda Te, where he demands that he return the SpellStone to its sacred land.
Although Fox was successful in returning the SpellStones, he learned that the planet required the six Krazoa Spirits to ensure Sauria's reconstruction. After Andross's defeat in outer space, the spirits were able to resume their protection of Sauria and returned DarkIce Mines, CloudRunner Fortress, Walled City and Dragon Rock back to the planets main surface.
General Pepper's ReportEdit
This is the detailed description that General Pepper gives to Fox for selection of both these items when contacting him:
Fire -"This is a Fire SpellStone from the Volcano Force Point. It contains Dark Matter which is used to hold the planet together."
Water - "This is a Water SpellStone from the Ocean Force Point. It contains Dark Matter which is used to hold the planet together."