From Halopedia, the Halo wiki
Blamex is a kind of high explosive employed by the Covenant remnants and Banished. It is manufactured from Subanese crystal (colloquially referred to as "Blamite") used in Needler ammunition.
Assault cannons: (Beserker's Claw • Wicked Grasp)
Misc: Infusion grenade launcher • Veporokk Workshop Ravager (Ravager Rebound)