Are there any normal difficulty boss modes that drop speed gems? I've been farming hard and hell and only getting str arm and hp gems.
I think it's still random the only thing that matters is the difficulty you set the Boss Mode room at, and +2 gems only drop at Hard difficulty and above
All Boss Mode chests drop all 6 types of gems. The best gems for upgrading come from Sejul Hell, D-H-08 Hell + Hard, and Al Hata Hard.