Core Concepts – Minerals, Rocks, and Resources
3.1a. Minerals have physical properties determined by their chemical composition and crystal structure.
Minerals can be identified by well-defined physical and chemical properties, such as cleavage, fracture, color, density, hardness, streak, luster, crystal shape, and reaction with acid.
3.1b. Minerals are formed inorganically by the process of crystallization as a result of specific environmental conditions. These include: cooling and solidification of magma; precipitation from water caused by such processes as evaporation, chemical reactions, and temperature changes; rearrangement of atoms in existing minerals subjected to conditions of high temperature and pressure.
3.1c. Rocks are usually composed of one or more minerals.
Rocks are classified by their origin, mineral content, and texture.
Conditions that existed when a rock formed can be inferred from the rock’s mineral content and texture.
The properties of rocks determine how they are used and also influence land usage by humans.
Related Core Concepts:
origin of matter in stars (1.2b)
reconstructing geologic history (1.2j)
rock cycle and plate tectonics (2.1m)
weathering of rocks and soil formation (2.1s)
