How many letters does the top answer for “a transparent purple variety of quartz; used as a gemstone” have?

The most common answer is amethyst (8 letters).

Crossword clue: a transparent purple variety of quartz; used as a gemstone

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

amethyst 8 letters wn-def

a transparent purple variety of quartz; used as a gemstone

a red transparent variety of zircon used as a gemstone 50% similar → hyacinth, jacinth