1. Naturally Occurring: Minerals form through natural geological processes, not from human intervention.
2. Solid: Minerals are rigid and have a definite shape and volume. They are not liquids or gases.
3. Specific Chemical Composition: Minerals have a fixed or variable chemical formula, meaning they are made up of specific elements in a definite ratio.
4. Defined Crystal Structure: Minerals have an orderly, repeating arrangement of atoms in a three-dimensional lattice. This arrangement determines their physical properties like hardness, cleavage, and crystal shape.
5. Inorganic: Minerals are not derived from living organisms. While organic materials like fossils can be embedded in rocks, the minerals themselves are inorganic.
Here's an analogy:
Imagine building a house.
* Natural occurrence: The house is built from materials found in nature, like wood or stone.
* Solid: The house is a solid structure, not a liquid or gas.
* Specific composition: The house is made of specific materials in specific ratios, like wood for framing, brick for walls, etc.
* Crystal structure: While not exactly "crystal" in the mineral sense, the house has a defined structure, with walls, floors, and a roof.
* Inorganic: The house is made from materials that aren't derived from living things.
Some examples of common minerals:
* Quartz: SiO₂ (silicon dioxide)
* Feldspar: (Na, K, Ca)AlSi₃O₈ (sodium, potassium, and calcium aluminum silicate)
* Halite: NaCl (sodium chloride, table salt)
Things that are NOT minerals:
* Ice: While it has a defined structure, it's not a naturally occurring solid on Earth (it's formed from water).
* Plastic: Plastic is synthesized, not naturally occurring.
* Coal: Coal is derived from decomposed organic matter, making it organic.
Understanding these five criteria helps differentiate minerals from other materials in the world.
