ROCKS

Rocks Around 3000 different minerals are found on Earth, however they are not found in pure form they are found in rocks. A rock is a solid, natural material made up of one or more minerals.

3 Types of Rocks 1. Igneous: form where hot, melted minerals cool and harden. Can form above or below surface

2. Sedimentary Rocks: form when bits of other rocks and the remains of living things are cemented together. Can form under bodies of water or on Earth’s surface.

3. Metamorphic rocks always form below Earth’s surface. Formed when heat, pressure or chemical reactions change igneous or sedimentary rocks

Igneous Rocks Deep below Earth’s surface, temperatures are o hot that they can melt minerals into magma. As this magma rises and cools it hardens creating igneous rocks.

Igneous rocks that form under ground are called intrusive rocks. Many intrusive rocks have large crystals and course grained texture. granite

Extrusive: magma that reaches Earth’s surface is called lava, when it hardens extrusive rocks are formed. Small crystals with fine grained textures

Sedimentary Rocks How do they form? Sediment is solid material like soil, pebbles and organic matter that are carried by air, water, or ice, and settle out.

How they are formed? They usually settle at bottom and through weight of other materials cement together. 75% of Earth’s rocks are Sedimentary

Types of Sedimentary Rocks 1.Clastic: made mainly from fragments of other rocks(most common sedimentary rock) 2.Chemical: form from chemicals dissolved in water(leave behind salt when water evaporates) 3.Organic: form from remains of living things

Metamorphic Formed from heat and pressure, 2 types 1.Foliated: minerals have been rearranged into visable bands 2.Nonfoliated: don’t show bands

ROCK CYCLE Series of natural changes that cause one type of rock to become another type of rock.