Education For Success

CHAPTER 1   ROCKS AND MINERALS AND THEIR EXTRACTION   The Earth is a rocky planet. It is made from rocks and metal ores, which makes it the densest planet in the solar system. This is mainly because the core consists of iron surrounded by a mantle of rock. What is a rock? A  rock  is a solid mass of geological materials. A  rock  is a solid collection of mineral grains that grow or become cemented together.   Formation of rocks: The planet Earth has formed about 4.5 billion years ago. The force of gravity pulled the heavier elements together first, forming the core. The lighter elements then formed the Earth’s crust about 3–4 billion years ago. The mantle developed as a layer between the dense core and the light crust. This structure still exists today.   The structure of the Earth:   1.   Igneous rocks :   Igneous rocks (from the Latin word for fire) form when hot, molten rock crystallizes and solidifies. ...