The Nuka Quantum grenade was a result of Project Cobalt's attempt at weaponizing the Strontium-90 isotope, nicknamed Quantum, that would later be used to create Nuka-Cola Quantum. The grenade looks identical to a Nuka grenade save for a glowing blue band around the lower half that hints at its origin and working principle. Like all quantum-based weapons, Nuka Quantum grenades detonate in a bright blue mushroom cloud, albeit a much smaller one than for example a Nuka-nuke's. Their damage rating is the same as a Nuka-grenade's minus the radiation component, which makes them the second-most destructive grenade type in the game.
Except for the two examples found next to the Project Cobalt schematics, Nuka Quantum grenades cannot be looted anywhere else in Nuka-World or the Commonwealth. Crafting them at a chemistry station from a fair amount of rare resources is the only way of acquiring them, though usually worth the cost for those hesitant to scavenge for Nuka-grenades due to the latter's enormous power.