Final answer:
A mineral is a naturally occurring, inorganic solid with a definite chemical composition and crystalline structure. These substances are essential components of rocks and vary from single minerals like quartz to mixtures of different minerals forming rocks such as granite, sandstone, and gneiss.
Step-by-step explanation:
A mineral is any solid mass of mineral or mineral-like matter that occurs naturally as part of Earth. Minerals are defined as naturally occurring, inorganic solids with a definite chemical composition and a characteristic crystalline structure. They are the basic building blocks of rocks, which can be made up of various combinations of minerals or just a single mineral. For instance, quartz, one of the most common minerals in the Earth's crust, consists of silicon dioxide (SiO2).
Being inorganic, a mineral must not contain complex carbon molecules characteristic of life, and it must exist in a solid form. For example, ice is considered a mineral when it occurs naturally because it is a solid and not man-made like synthetic bismuth. Minerals possess a specific chemical formula such as NaCl for halite, or (Mg,Fe)2SiO4 for olivine, where the magnesium and iron content can vary. Their atoms are arranged in an orderly pattern, resulting in their crystalline structure.