callous
calloused
curable
enured
hardened
inured
sunbaked
thickened
weather-beaten
annealed
backed
calcified
case-hardened
crusted
crusty
crystallized
fossilized
granulated
hornified
incrusted
indurate
indurated
lapidified
ossified
petrified
reinforced
rigidified
sclerotic
set
solidified
steeled
stiffened
strengthened
tempered
vitrified