ROCKS AND MINERALS

The three main types of rocks.
1. Sedimentary
2. Metamorphic
3. Igneous

SEDIMENTARY

• Sedimentary rocks form in layers over a long time.
• In sedimentary rock you would find bits of shell, pebbles, other bits of material and sand washed down by water.
• Sedimentary rock is known as a soft rock.

METAMORPHIC

• Metamorphosis means rock changing from one type to another.
• These types of rocks are made under the earth. They are formed by lots of heat and pressure. You might see tiny crystals in these rocks. They are known as hard rocks.
• Metamorphic rocks include quartzite, slate and marble.

IGNEOUS

• Igneous rocks are formed from molten rock.
• The molten rock material that is under the earths crust is magma. When it cools it makes igneous rock.
• Molten rock that is forced out of the earth is called lava. Lava erupts from volcanoes.
• Key words to describe igneous rocks are molten rock, magma and lava.
• 2 types of igneous rocks are granite and basalt.
• Under heat and pressure igneous rock can change into metamorphic rocks.

MOHS SCALE

• MOHs scale is used to measure the hardness of minerals.
• Diamond is the hardest mineral on the MOHs scale. It has a rating of 10.

MOHS SCALE

• Quartz is a mineral with a hardness of 7. Quartz is an igneous rock. Some quartz have large crystals and some have small crystals, depending on how it's cooled. Some quartz you can even see through.

COLOUR AND STREAK OF MINERALS

• Sometimes the colour and streak of minerals are very different.
• Specular hematite in colour and has the greatest difference streak.
• Speculate hematite is silver but it's streak is red/brown.

THE END