Mixtures

A mixture is a substance made by combining two or more different materials in such a way that no chemical reaction occurs. A mixture can usually be separated back into its original components.

Most natural substances are mixtures. eg: Graphite

A homogeneous mixture has the same uniform appearance and composition throughout. Many homogeneous mixtures are commonly referred to as solutions.
A heterogeneous mixture consists of visibly different substances or phases. The three phases or states of matter are gas, liquid, and solid.