Mineral used in drywall (4)

I believe the answer is:

mica

(Other definitions for mica that I've seen before include "Isinglass" , "Shiny silicate mineral" , "Transparent mineral" , "Muscovite with perfect cleavage" , "Flexible mineral found in igneous and metamorphic rocks" .)

I've seen this clue in The New York Times and The Wall Street Journal.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.