Micas are a group of silicate minerals known for their layered structure, which allows them to be easily split into thin sheets. They are commonly found in igneous and metamorphic rocks and are often used in various applications, including cosmetics, electronics, and construction materials. The most common types of mica are muscovite and biotite. These minerals have excellent insulating properties and can withstand high temperatures, making them valuable in industries such as electronics for capacitors and insulators. Micas also have a shiny appearance, which is why they are often used in makeup products like eyeshadows and highlighters to add shimmer.