A mineral is a natural substance that is represented by a chemical formula and has an ordered atomic structure. It is usually solid and stable when at room temperature. A rock is an aggregate of minerals. Rocks are classified by their composition of different minerals.

Minerals can be classified by:

Chemistry - dependent by element abundances in the Earth

Crystal Structure - the geometry of the internal structure

Hardness - how much it can resist scratching

Lustre – how it reflects light

Colour – the mineral’s colour

Clevage – the planes and the angles of those planes

Specific Gravity – the density of the mineral

Rocks are classified by three groups:

Igneous Rocks – forms through the cooling of lava

Sedimentary Rocks – forms by the deposition of rocks and organic matter

Metamorphic Rocks – the transformation of existing rocks

Examples of each:

Rocks (minerals they may contain in parentheses):

Granite(Quartz, Mica, Feldspar)

Marble (Calcite, Dolomite)

Schist (Mica, Chlorite, Talc, Hornblende, Graphite, Quartz, Feldspar)

Minerals (chemical composition in parentheses):

Quartz (SiO₂)

Calcite (CaCO₃)

Graphite (C)

Talc (H₂Mg₃(SiO₃)₄)