https://na.finalfantasyxiv.com/lodes...flict/reward/7

Seems like Diamond gets 1 Commendation Crystal, Crystal gets 2 and Top 100 gets another 2 so 4 total.

I've heard some saying that 1 is enough for weapons but considering T100 gets 2 extra, it's highly likely that it requires 2 crystals per weapon. Unless they plan to drown people in them.