How many letters does the top answer for “a variety of the mineral called petalite, from elba.” have?

The most common answer is castor (6 letters).

Crossword clue: a variety of the mineral called petalite, from elba.

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

castor 6 letters web-def

type genus of the Castoridae: beavers

castorite 9 letters web-def

A variety of the mineral called petalite, from Elba.