[Kidd isn't the only one that the mentions of crystals with different colors snap his recollection back to that note as well and almost as if he were expecting Kidd to have kept a hold of it, he's fishing immediately into his inside pocket to draw out his own hardback notebook.

Flicking through page after page he finally holds the book out alongside Kidd's note, so that those who can't read the Ancient writing can read his translation.]

Sapphire is for 'total defense'. [The quotation marks in his tone of voice were as obvious as if they might be written]

I might suggest that ruby crystals are for the red circle - to attract the Calamity towards a certain location.

[Sephiroth isn't letting go of his notebook but everyone is welcome to come and look.]

Perhaps this location really is already 'protected' from the Calamity, already.