1) Change into stone 2) Fossilise 3) Fossilize 4) Petrify 5) To become stone or stony 6) To petrify 
• (v. i.) To become stone or stony. • (v. t.) To convert into stone or stony material; to petrify.
La·pid'i·fy transitive verb [ imperfect & past participle Lapidified ; present participle & verbal noun Lapidifying .] [ Confer f. lapidifier . See Lapidific , and -fy .] To convert into stone or stony material; to...
[v] - change into stone
lapidify Related 'stone, rock' word families: litho-; petro-; saxi-; stele-.
petrify verb change into stone; `the wood petrified with time`