Mica

minerals · rocks · sparkly · geology

Splits into sheets. Mica crystals have a special property called perfect basal cleavage, which means they naturally peel apart into thin, flaky layers. You can actually split a piece of mica with your fingernails if you're careful.

Found in many rocks. Mica is super common in igneous rocks (formed from cooled lava) and metamorphic rocks (changed by heat and pressure deep in the earth). You might spot tiny mica flakes glinting in granite countertops or sidewalks.

Mica books exist. In some rare places called pegmatites, mica forms enormous sheets stacked like a giant book, sometimes several feet across. These natural mica books are treasured by rock collectors and miners.

See-through and bendy. When mica splits into thin plates, they're elastic, meaning they can bend and flex without breaking easily. This makes the sheets slightly see-through and kind of sparkly.

Born from heat. Mica forms when rocks are created or changed by extreme heat and pressure inside the earth, or when molten material cools down slowly underground.