Mineral that shimmers (4)

I believe the answer is:

mica

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

I've seen this clue in The New York Times.

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.