Do mollusks have a spiny or leathery covering?

Mollusks do not have a spiny or leathery covering; instead, they typically possess a hard external shell made of calcium carbonate, which can be smooth or textured. Some mollusks, like octopuses and squids, lack a traditional shell and have a more flexible body structure. The shell serves as protection for many species, while others rely on camouflage or other adaptations for defense.