This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

v. To turn sediment into solid rock

To convert into stone: more commonly petrify.

To become converted into stone.

"Re “The crinoid would have to be buried in a marine environment; the sediment would have to lithify and turn to chert SiO2; then be weathered and a chert fragment swallowed by a dinosaur; …”"

lithification   

petrify