This unit we are about to start talks about Rocks and minerals, how they were formed in nature and what uses humans make of them.
There´s two main elements we are going to study in this unit: minerals and rocks. We will start by differentiating them.
Rocks are formed through 3 different processes that take place in nature.
Minerals have different characteristics:
- Hardness
- Lustre: how shinny it is.
- Color: what color is it.
- Streak: the color of the powder within the mineral.
- Cleavage and Fracture: If a mineral breaks apart and it breaks straight and flat then it is called cleavage.
Different types of Rocks
formed by the cooling and solidification of magma and lava.
2- Sedimentary Rocks:
They are made from sediment or by chemical reaction. Sediment is loose material like bits of rock, minerals, plants, and animals.
3- Metamorphic Rocks:
It is made below the Earth's surface where pressure and heat are high. Metamorphic means transformation, this means that the rocks can change physically and chemically over a long period of time.
The Rock Cycle:
The rock cycle is what happens to rocks when they change into different types of rocks. When an igneous rock is changing into a sedimentary rock it has to become sediments first. It does that by weathering and eroison, once it has become sediments then from compaction and cementation the igneous rock can turn into a sedimentary rock. An igneous rock can also turn into a metamorphic rock. It can do this by crystalization. Sedimentary rocks can turn into metamorphic rocks to, they can do this by heat and pressure. Metamorphic rocks can turn into sedimentary rocks by weathering and eroison, they can also turn back into igneous rocks by heat, the heat melts the rock into magma and them the magma is hardened and is turned into an igneous rock.
WATCH THIS VIDEO TO UNDERSTAND THE FORMATION OF THE ROCKS
