3.1a Minerals have physical properties determined by their chemical composition and
¥ Minerals can be identified by well-defined physical and chemical properties, such as
cleavage, fracture, color, density, hardness, streak, luster, crystal shape, and reaction
¥ Chemical composition and physical properties determine how minerals are used by
3.1b Minerals are formed inorganically by the process of crystallization as a result ofspecific 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 rocks mineral
content and texture.
¥ The properties of rocks determine how they are used and also influence land usage by humans.