How are mountains classified into different types according to their mode of formation?

Mountains are often classified according to their mode of formation.

1. Fold Mountains — Formed by the folding or buckling of the earth's crust due to forces of compression. For example, the Andes, Rockies and Himalayas.
2. Block Mountains — Formed due to faulting (because of tensional forces), which results in the earth's crust breaking into blocks. When a crustal block subsides along the fault plane, it leaves behind two uplifted blocks on each side. These uplifted blocks are called Block mountains. For example, Satpuras, Sierra Nevada and Harz Mountains.
3. Volcanic Mountains — Formed when magma along with ash and small rocks particles erupt from a volcano and on reaching the surface, it cools down and solidifies around the vent. The lava piles up gradually, thereby building up a conical volcanic mountain. For example, Mt Etna and Mt Fujiyama.