2RocksA rock is a naturally occurring solid that is usually made up of one or more types of minerals.
3How are rock classified? Rocks are classified by how they are formed, their composition, and texture. There are three main categories of rock: igneous, sedimentary and metamorphic.
4Rock CycleRocks change over time through the rock cycle. The rock cycle is the set of natural processes that form, change, break down and re-form rocks. It is a continuous process; therefore it has no beginning and no end.limestoneGabbro
5Few rock types do not contain any minerals at all. Ex. Obsidian which is made of natural glass, which is not a mineral because it doesn’t have a crystal structure.Ex. Coal is made up of the remains of ancient plants that have been buried and pressed into rock.coalObsidian
6Rock Types Rocks are classified by how they form. The 3 types of rocks are:Igneous rocksSedimentary rocksMetamorphic rocks
8Igneous RocksIgneous rocks are formed from melted minerals that have cooled and hardened.The term “igneous” means born of fireThere are two types of igneous rocks: intrusive and extrusive
9Intrusive Igneous Rocks Intrusive igneous rocks are formed underground from cooled magma. They have large crystals because magma deep below the surface cools slowly.Most common Intrusive Igneous= Granite
11Extrusive Igneous Rocks Extrusive Igneous rock is formed from cooled lava on the Earth’s surface. They have small crystals because lava cools too quickly for larger crystals to form.Most common Extrusive Igneous rock= Basalt (The Hawaiian Islands are made of Basalt, resulting from volcanic eruptions.)
15Sedimentary RocksSedimentary rocks are formed by weathered (breaking a rock down) and eroded (moving the broken pieces) bits of sediments like sand, soil, pebbles, and the remains of dead plants and animals are deposited(where they land). As the layers settle on top of each other they get compacted and cemented (pressed and hardened) together to make a Sedimentary Rock.
16Three types of Sedimentary Rocks: ClasticChemicalOrganic
17Clastic RocksClastic – form from fragments of other rocks. These are the most common types of Sedimentary RocksExamples: Shale, Conglomerate, SandstoneExamples are: Shale, Conglomerate, Sandstone
18Chemical Rocks Chemical – form from chemicals dissolved in water. Example: Limestone, Rock Salt, Gypsum
19Organic Rocks Organic – form from the remains of living things. Example: Limestone is made from shells of clams and mussels that pile up on the oceanfloorDid you know? Limestone makes chalk!
21Metamorphic RocksMetamorphic rocks are formed by heat and pressure from deep inside the Earth. This heat and pressure squeezes, bends or bands, and twists rock from all sides. Hot fluids move through the rock. The heat, pressure, and liquids can change the texture and look of the rock.
22Foliated Metamorphic Rock Foliated metamorphic rocks have visible bands. You see the layers within the rocks.Examples are: Slate, Gneiss and Schist
23Non-Foliated Metamorphic Rock Non-foliated are metamorphic rock that do NOT have visible bends or bands.Example: Marble
24What forces are being added to the candy? ____ and ____ Metamorphic Rock LabProcedures:Unwrap the starburst.Stack the starburst on top of each other in the open palms of your hands.Push your palms together slowly. (Do Not Twist!)Hold the candy for 3 minute.Open your hands.Observe the candy.Materials:3 Different Colored StarburstAnalysis:Why did each student receive 3 different colored starburst? What does it represent?What forces are being added to the candy? ____ and ____ 3. What did you observe after completing the experiment?4. Is this an example of a foliated or nonfoliated metamorphic rock? 5. Explain how a metamorphic rock is formed.