outer layer, husk / crust / cuticle

Solid, hard, firm.

edible fruit that grows on trees or shrubs, such as oranges and apples, or sweet edible fruit that grows along the ground, such as strawberries and melons

(rare) fruit

Keeping a material's shape that does not crack or break apart; hard / Keeping one's appearance or facial expression; serious

a hard palate

anhydrite

dried fruit (small fruit that have been preserved by drying)

Tang confectionery

硬い: keeping its physical shape or appearance under a force: stiff / 固い: keeping its shape or behaviour even under other influences: hard, firm