Book 27, Question 98
What is mica, and why does it peel into thin sheets?
Mica is a shiny mineral made of stacked flat layers.
The layers are held together only weakly, so you can peel them apart into thin, flexible, transparent sheets. Mica handles heat well and does not conduct electricity, which made it useful for old oven windows and electronics. Powdered mica puts a shimmer in some paints and makeup. In the sand, you may see small flashing flakes of it.