Minerals: Quartz is primarily composed of

Quartz consists of silicon dioxide (SiO₂) and is one of the most abundant minerals in Earth's continental crust. It forms hexagonal crystals and exhibits excellent hardness (7 on the Mohs scale), making it resistant to weathering. Quartz occurs in many varieties including clear rock crystal, purple amethyst, yellow citrine, and smoky quartz. It has numerous industrial applications including glass manufacturing, electronics (quartz crystals in watches and computers), and as an abrasive material. Its piezoelectric properties make it valuable in precision instruments and oscillators.