Elements, I wonder why they didn't do this.

[seiferalmasy2]

Well there is an Holy materia- alexander.

But yes it would have been more complicated. There were a lot of things in FF7 dropped or not completed (1:35 Shinra soldier) due to time constraints.

FF7 does have a tutorial built in which explains each and you can place each of them onto a weapon or armours.

The elments (attributes) are:

Fire, Ice, Lightning, Earth, Wind, Water, Holy, Gravity

(poison is a status magic not an attribute/elemental)

I Don't buy the holy vs aerith connection because there are TONS of references to Meteor in the game which are nothing to do with black materia.