Cast iron is a nearly indestructible material that's ideal for grinding foods.
Its coarse surface creates more friction to release aromatic compounds from spices and herbs and achieve a finer texture. And smart design details make this set especially effective: The pestle that comes with the mortar has a thinner handle that's easier to grip, with a knob near the handle that keeps it from slipping out of your hand. There is a heavier knob at the other end with a wider surface area, which directs force more effectively onto spices so you don't need to exert as much energy.