Minerals are naturally occurring, solid inorganic substances with a defined chemical composition and a characteristic crystal structure. Here are three examples:
1. Quartz: A common mineral composed of silicon dioxide (SiO2). It comes in various colors and forms, like clear rock crystal, smoky quartz, and amethyst.
2. Feldspar: A group of minerals that are the most common rock-forming minerals on Earth. They are typically white or pink and have a glassy luster.
3. Gold: A metallic element that is highly prized for its beauty and value. It occurs naturally in nuggets, veins, and deposits.
