Change Into Rock Such as Limestone

This page is the CodyCross answer for the clue below from Cats, Group 1721, Puzzle 1 (Furry Friends).

Question is: Change Into Rock Such as Limestone

and the answer is: CALCIFY

Word Meaning:

CALCIFY — (transitive, intransitive) To make or become hard and stony by impregnating with calcium salts.

Definitions from Wiktionary.