crisp

fragile, frangible, brittle, crisp, friable mean breaking easily.

fragile implies extreme delicacy of material or construction and need for careful handling.

frangible implies susceptibility to being broken without implying weakness or delicacy.

brittle implies hardness together with lack of elasticity or flexibility or toughness.

crisp implies a firmness and brittleness desirable especially in some foods.

friable applies to substances that are easily crumbled or pulverized.