Synonyms and related words :
backed, bone, bony, calcified, callous, calloused, case-hardened, crusted, crusty, crystallized, fossilized, granulated, hardened, hornified, incrusted, indurate, indurated, lapidified, osseous, ossicular, ossiferous, osteal, petrified, reinforced, rigidified, sclerotic, set, solidified, steeled, stiffened, strengthened, toughened, vitrified