calcify (verb) – to make something hard, rigid, or bony; to harden using calcium salts
BREAKDOWN: CALC- (calcium) + -FY (to make or do)
— calcification is a change into a stony or calcareous substance; a hardening or solidifying
This word is built on the root CALC-, which means small stone, pebble used for counting, lime or calcium, or heel.
Common CALC- words include calcium, calculator, chalk, and miscalculate.
More esoteric CALC- words include calx, calcareous, and calculous.