Mica is a type of mineral that splits naturally into thin, transparent sheets, almost like the pages of a book but much more delicate. These sheets are remarkably heat-resistant and don't conduct electricity, which makes mica useful in many practical applications.

If you've ever noticed tiny sparkly flakes in sand, on a rock, or even in some types of makeup, you were probably seeing mica. The flakes catch light beautifully because they're flat and slightly transparent. Geologists can often peel mica apart layer by layer with their fingernails.

Because mica can withstand high temperatures without burning or melting, it was once commonly used in the small windows of wood-burning stoves, allowing people to see the fire inside without the window breaking from the heat. Today, manufacturers use mica as an insulator in electrical equipment, helping prevent short circuits and fires. Ground-up mica also adds shimmer to paints, cosmetics, and even the sparkly bits in some concrete.