versus

Rock on!

Igneous Rocks …are solidified from mineral matter in a high-temperature molten state.

Sedimentary Rocks …are layered accumulations of mineral particles derived mostly by weathering and erosion of preexisting rocks.

Metamorphic Rocks …are formed from rocks that have been physically or chemically changed, usually by application of heat and pressure during crustal mountain-making.

Difference between Minerals and Rocks A mineral is a solid, inorganic, naturally-forming material of the Earth that has both a known chemical composition and a crystalline structure with distinct physical properties that is unique to that mineral A rock is a solid aggregate of one or more minerals that have been cohesively brought together by a rock- forming process.

Igneous Rocks -‘Fire’ rocks -Formed either underground or above ground. -Underground, they are formed when magma becomes trapped in small pockets and cool slowly (intrusive) -Above ground, igneous rocks form when volcanoes erupt, causing magma to come to the surface (called lava) and cools (extrusive)

Igneous RockObservable Characteristics Location of Formation Example Volcanic (Extrusive)Crystals so small you can't see them with the unaided eye. Sometimes there are larger, visible crystals in a very fine-grained matrix. These rocks were once liquid magma that erupted from volcanoes. They cooled very quickly, which is why the crystals are usually very small. Basalt – usually dark gray to black, fine- grained volcanic rock; sometimes has gas bubbles (vesicles) IntrusiveInterlocking CrystalsThese rocks were once liquid magma, but they did not erupt from volcanoes. Instead, they cooled slowly underground. The crystals had time to grow large. We see them because erosion has stripped off and removed all of the rock above it. Granite – pinkish, whitish igneous rock with interlocking crystals of quartz and feldspar. Sometimes includes mica.

Igneous Rock Classification Common Igneous Rocks ClassificationIgneous Rock ColorCommon Minerals Intrusive Igneous Rocks GraniteFelsic (light-colored) Quartz, potassium feldspar, plagioclase feldspar, mica DioriteIntermediatePlagioclase feldspar, amphibole, pyroxene, mica GabbroMafic (dark-colored) Plagioclase feldspar, pyroxine, olivine Extrusive Igneous Rocks RhyoliteFelsicQuartz, potassium feldspar, plagioclase feldspar, mica AndesiteIntermediatePlagioclase feldspar, amphibole, pyroxene, mica BasaltMaficPlagioclase feldspar, pyroxine, olivine PumiceFelsic/Interme diate Various silicates ObsidianVariableVarious silicates

Sedimentary Rocks -‘Water’ rock -Over millions of years, rocks are eroded and weathered and transported by wind and water to eventually settle in the bottom of rivers, lakes or oceans. -Layer after layer of eroded earth are deposited on top of each other. -These layers are compressed over time, until the bottom layers slowly turn into rock under great pressure. -These layered rocks that form are called sedimentary rocks

SedimentaryObservable Characteristics Location of Formation Example ClasticMade up of smaller rocks cemented together. Sometimes has fossils. Usually has layers. These rocks formed when loose sediment (rocks, sand) were deposited by water, compacted, and cemented together. These rocks form along beaches, by rivers, or under the water in lake or oceans. Conglomerate – composed of pieces pebble-size or larger Sandstone - composed of sand- size pieces Shale - composed of pieces smaller than fine sand ChemicalUsually a light gray, sometimes with crystals, sometimes with shells, sometimes just massive. These rocks are also deposited in water. However, they form as a chemical reaction in the water that leaves a chemical deposit, usually on an ocean bottom. Limestone – a whitish or grayish rock made of the mineral calcite.

Sedimentary Rock Classification Common Sedimentary Rocks Classificati on Sedimentary Rock CompositionDepositional Environment Clastic (Detrital) ShaleClay and/or siltSwamp, floodplain, river bottom SandstoneSandBeach, desert Conglomerat e Various-sized pebbles Riverbed Non- Clastic (Chemical) LimestoneCalcite or fragmented shells Shallow sea, coastline Chert (flint)Chalcedony (quartz), traces of other minerals Formed from a silica-rich precipiate in a deep ocean environment. Bituminous Coal Plant materialAncient forest or swamp

Metamorphic Rocks -Rocks that have "morphed" into another kind of rock -Morphing happens under tons of pressure, which fosters heat build up, and this causes them to change. -This explains why some metamorphic rock samples have flattened grains.

MetamorphicObservable Characteristics Location of Formation Example Usually has interlocking crystals and layers (called foliation) These rocks formed when igneous, sedimentary, or other metamorphic rocks are heated and/or squished, forming a new rock type. This usually happens during mountain building events (regional metamorphism), but also happens during igneous activity (contact metamorphism). Quartzite – metamorphosed sandstone Slate – metamorphosed shale. Schist – metamorphosed sedimentary rocks that had lots of clay. Gneiss – metamorphosed granite.

Metamorphic Rock Classification Common Metamorphic Rocks Classificat ion Metamorph ic Rock Parent RockCommon Minerals Foliated (Banded) SlateShale, mudstoneQuartz, clay minerals (feldspars) SchistShale, slate, basalt, or graniteMica, chlorite, talc, quartz GneissShale, schist, granite, sandstone, and other rock types Quartz, feldspars Non- Foliated (Not Banded) QuartziteSandstoneQuartz MarbleLimestone, dolomiteCalcite Anthracite coal Bituminous coalCrystalline carbon