Crystal equipment

[Manly Man]

How's about materia that the crystal's element would either be strong or weak against makes you double the MP cost from the clashing energies (you would have to spend 6 MP for 3d6 of fire damage if you have an Ice or Water materia in a Fire crystal weapon, or you'd have to spend 1 MP for each point of elemental resistance from your Wind crystal armor if you have Ice or Earth materia in it)? Having a materia of the same element gives your weapon or armor the broken condition if you activate either the materia or the crystal, and doing it with broken equipment destroys it instead. Going this route with crystal-materia relationships does give the suggestion of armor protecting you against its own element more support.

I do have some ideas for other materials and such, like having Wurtzite from XIII be Adamant+ with some magic-resistant properties (I know that wurtzite in real life is actually pretty soft and fragile stuff, but bear with me here, if Adamantortoises were originally supposed to be replaced with a Wurtzitoise and Adamant Bangles upgrade to Wurtzite Bangles, then I'll stick to that logic).