Magical Lore

I was wondering if possible I could make some of the magical lore for the game. I want to make it loose so people have freedom but also have some limitations such as Diamond is type of substance that has a negative affinity towards magic due to its composition. Thus when enchanting a diamond tool or armor, the magic user must use a lot of magical force (exp) to compensate for its negative affinity. Thus magic users will have a hard time enchanting diamond tools and armor continuously without exhausting their's or someone elses mana and increasing their overall fatigue. Sorry it's like 6 am over here so I might not be making much sense. Anyways if I write some things about magical lore and get them approved by the co-owners or owner or the group in general, can we use them or do you already have a set idea. This is just mana and magic in general I am not going to get in specifics with the types of magic unless you want me to.