How many letters does the top answer for “forming or converting into stone.” have?

The most common answer is lapidific (9 letters).

Crossword clue: forming or converting into stone.

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

lapidific 9 letters web-def

Forming or converting into stone.

lapidifical 11 letters web-def

Forming or converting into stone.

the stone forming a threshold. 50% similar → doorstone