What Is The Difference Between Rocks Minerals And Gems?

A rock is considered to be an ordinary object that is not worth much.

But certain rocks contain materials that people find useful, they could then be considered a mineral. Mineral rich "rocks" are sometime known as "Ore". An example might be iron ore. Iron ore can be refined into iron, a very useful material.

Some rocks contain or are made of other materials that people find valuable because of their appearance. These materials could be quartz or even diamonds. When removed from the surrounding rock these materials can be cut or polished and will then be known as "Gems".