Rock is a solid heterogeneous mixture of one or more minerals.
For example, granite is a mixture of the minerals quartz, feldspar, and biotite.
A mineral is a naturally occurring solid that has a crystalline structure and a definite chemical formula.
For example, gibbsite is a mineral of aluminium with the formula Al(OH)3.
When is a rock considered an ore is a rock that contains minerals in concentrations that are high enough for economical extraction.
For example, bauxite is an aluminium ore.