Final Fantasy VII Guides and Walkthroughs
The All Materia can be paired with any Magic (Green) Materia and instead of that spell hitting just a single enemy, it hits all enemies on the field. Depending on how much you've mastered the Materia determines how many times you'll be able to use 'All' on the enemies. Three stars towards mastering it and you can use All three times during a single battle.
Pairing another Materia with All reduces the effectiveness of that Materia down to 1/3. Since it hits all targets, that's your trade off. I'm not going to go into much more detail about All since this is the easiest one to figure out amongst all the Materia.
Where to buy All Materia:
Fort Condor (Disc 2/3) - After you complete the Huge Materia quest this will be for sale here
Useful All Materia Combinations
Restore + All - this is a Materia combination you're going to want on everyone in your party in my opinion
Return to Materia Combinations Guide