Earth and Air Universal Array

I was bored one day, and decided to look up Alchemy myths and stuff. I ended up with a cool symbolism of alchemy site, and decided to make my own Fullmetal Alchemist transmutation circle.

If I did it right (which I think I did) this circle would be able to manipulate Air, any metal containing iron, and anything made of stone. The symbol on the top is the symbol for stone, the symbol on the right is the symbol for Air, the symbol on the bottom is for iron, and the symbol on the left means "purity" or "perfect". The lettering in the centre means "in equal amounts" which i put in just because of the law of equivalent exchange.

I'd like to note this is a first attempt, and it is very likely all wrong, but you never know.