Tales of Symphonia Tips & Tricks

After receiving special items from the Summon Spirits, you can change your weapon's element in order to deal more damage to some enemies. For example, using Water against a Fire-type enemy. Incidentally, some of these allow special techniques once conditions are met. Refer to the "Special abilities" hint for details.
Amethyst: Attack Element turns to Darkness.
Aquamarine: Attack Element turns to Water.
Garnet: Attack Element turns to Fire.
Opal: Attack Element turns to Wind.
Ruby: Attack Element turns to Earth.
Sapphire: Attack Element turns to Ice.
Sardonyx: Attack Element turns to Lightning.
Topaz: Attack Element turns to Light.

When you can repeatedly fight in colloseum, keep entering, and in about 30 min. you should have about 1mil.