Unit II Rocks and Minerals Make sure that you copy down all the red information into your note packet.

A. Minerals - that have a definite chemical composition and molecular structure. -classified on the basis of their Their and their Naturally occurring, solid, inorganic substances Physical and chemical properties Chemical composition Structure

Identification Don’t rely on color only to identify minerals 1. color- many minerals are found in a variety of colors. - many minerals have the same color.   2. _________- color of a mineral in its powdered form. -more reliable than color. 3. _________- the way in which light is refracted from the surface of a mineral. a._______________- shine like polished metals. b._______________- no metallic shine. -glossy, pearly, greasy, dull, earthy, etc. Quartz Streak Luster Metallic Nonmetallic FYI - Metallic minerals usually have dark colored streaks.

Identification 1Talc 2Gypsum 3Calcite 4Fluorite 5Apatite 6Feldspar 4. Hardness- the resistance of a mineral to being - is used. - glass has a hardness of 5.5. scratched Moh’s Scale Softest Hardest Fingernail 2.5 1Talc 2Gypsum 3Calcite 4Fluorite 5Apatite 6Feldspar 7Quartz 8Topaz 9Corundum 10Diamond Steel knife (nail) 5

Mica – 1 direction, sheets, Halite – 3 directions, cubic Identification 5. ___________- the tendency of a mineral to split along one or more smooth, flat surfaces, or planes.   6. ___________- minerals that don’t have cleavage fracture when they break. 7. others- magnetism, may react with acid, double refraction (look through it and see double), taste, etc. Cleavage Mica – 1 direction, sheets, Halite – 3 directions, cubic Fracture Quartz, Magnetite, Garnet Internal arrangement of atoms determines if there is cleavage or fracture.

Composition of the Earth’s Crust Two most abundant elements Make up a family of minerals known as the Silicates

Choose the minerals from the silicate family

Internal Arrangement of Atoms The arrangment of the tetrahedral units controls: Breakage Hardness Crystal Shape

Rocks composed of one or more - there are over different minerals. - % of all rocks are composed of ten to fifteen different minerals called rock-forming minerals. minerals 3,000 90

Igneous Rocks - form as a result of ____________- molten rock beneath the Earth’s surface. ____________- molten rock that has reached the Earth’s surface. -most igneous rocks are (made of one or more minerals). - when molten rock solidifies, it crystallizes into igneous rock. - the crystals are made of different minerals. solidification of molten (melted) rock Magma Lava polymineralic

Igneous Rocks a. texture- the grain appearance. -depends on the of the crystals and their arrangement within the rock. - cooling time- affects the size of the crystals. - long cooling time ____________ crystals. - short cooling time ____________ crystals. -very quick cooling- no grains form- rocks have a glassy texture obsidian. size large small - crystal shape – result of internal arrangement of atoms

Igneous Rocks questions: Where would rocks cool slowly vs. quickly? Where would a rock with large crystals have been made?   Where would a rock with small crystals have been made? Deep in earth’s crust where pressure and temperature are great. Called Intrusive Igneous Rocks At or near the earth’s surface (volcanoes). Called Extrusive Igneous Rocks Formed deep in the earth’s crust. Example – Granite Formed at or near the earth’s surface. Example – Basalt

Using the Igneous Rock Chart Can you find these on the chart? Extrusive Intrusive General Characteristics Textures Mineral Names Rock Names

Mineral Composition Coarse Granite You need to be able to identify the minerals in the rock to use this section of the chart. Big grain size, so the texture is? Based on this information the rock name is? Coarse Granite

Finding the Rock Name Using Mineral Percents Estimate the percent of each mineral in the rock (± 5%) Plagioclase Feldspar Pyroxene Olivine Amphibole 30% 60% 5% The red line represents the mineral composition of the rock. 5% The total must equal 100%

Try This One Peridotite Mineral Percents 25% Pyroxene 75% Olivine Coarse Texture Rock Name is Peridotite

Andesite Try This One Mineral Percents 25% Amphibole 15% Biotite 60% Plagioclase Fine Texture (nonvesicular) Andesite Rock Name is

Sedimentary Rocks most form as a result of of broken rock material. These broken pieces of rocks or sediments are usually deposited in large . As they tumble down the streams and rivers that carry them, they tend to become . some form from chemical or biological processes. compression and cementation bodies of water (lakes and oceans) rounded

Sedimentary Rocks All Clastic Sedimentary rocks form this way. a. compression pressure created by and overlying can be great enough to force particles of sediment close together, drive out any water present, and compact the sediments into a rock. __________- forms from tiny particles of clay water sediments Shale All Clastic Sedimentary rocks form this way.

Sedimentary Rocks b. _______________ when minerals such as silica, lime or iron oxide are added to sediments it tends to “glue” them together. often gives the rock their color Sedimentary rocks often show layering due to deposition on water. Sediments are sorted by size, shape, and density as they settle to the bottom Cementation Gray or white from silica or calcite (lime). Red, brown or rust-colored from iron oxide

Sedimentary Rocks c. chemical processes - - As water holding dissolved ionic minerals evaporates, it can’t hold all the minerals and they precipitate (fall out) of the water. Forms rocks with a mass of intergrown crystals. - evaporites- Formed by the evaporation and precipitation of sea water. Also called Crystalline Sedimentary rocks Rock salt – left behind after evaporation of ocean water.

Sedimentary Rocks Fossil and Rock Formation d. biological processes - rocks formed from _______________- compression of dead plant materials _______________- compressed and cemented corals and shellfish   e.__________- remains or impressions of plants and animals found in rocks. - usually found in once living things (organic matter) coal limestone Called bioclastic sedimentary rocks fossils all different kinds of sedimentary rock.

Sedimentary Rocks Look for the following: Layers of sediments. Pieces of other rocks cemented together. Evidence of fossils Sandstone Conglomerate Shale with Trilobite

Sed. Rock Groups Clasitic (fragmental) Look for visible sediments Particles usually rounded Sorted by size of sediments Include: conglomerate, sandstone, shale

Sed. Rock Groups Crystalline (evaporites) Rocks formed from evaporating sea water Chemicals combine and settle to bottom of the ocean Usually monominerallic Include limestone, rock salt and rock gypsum .

Sed. Rock Groups Bioclastic (Organic) Formed from once living material Usually contain a lot of fossils Include limestone and coal Fossil limestone Coquina

Sedimentary Rocks and The Rock Cycle Compression and Cementation The blue and green arrows show what happens to sedimentary rocks.

Very Important Information Reference Table Chart 3 Major Groups Very Important Information

Metamorphic Rocks - classified according to their   - form as a result of the recrystallization of __________ rocks. - occurs under conditions of extreme over long periods of time. texture, grain size and composition. Also if they exhibit banding or foliation. unmelted heat and pressure - pressure increases the density of the rock, usually makes it harder to weather.

Metamorphic Rocks recrystallization- process in which rocks - as a result of heat and pressure minerals in rocks combine to form new, crystalline structures. - crystals often form in the rocks (gneiss) - marble and quartzite have crystals larger than the crystals in the original rock they came from undergo change without melting. larger, denser, distorted layer-like bands (banding)

Metamorphic Rocks contact metamorphism- when molten rock comes in contact with existing rock, heat causes recrystallization of the rock materials and changes them into a new rock.

Regional Metamorphism Example of Regional metamorphism Occurs during mountain building and movements of the crust. Deeply buried rocks are subjected to high heat and pressure. Hot liquids and gases in the deep rocks can speed up the process.

Metamorphic Rock Chart Two main groups. Foliated Nonfoliated

Main Characteristics Gneiss Look for bands of different color crystals Look for distorted bands of crystals.

Main Characteristics Marble Quartzite More crystalline More Dense Bigger crystals Deformed bands Distorted crystals

Using The Metamorphic Rock Chart Three obs. Classify these rocks Grain size Composition Texture You’ll find a lot of information here.

Rock Samples: Foliated

Rock Samples:Nonfoliated More crystalline

Is this rock foliated or nonfoliated? Marble What is this rock called?_____________________

Is this rock foliated or nonfoliated? Gneiss What is this rock called?_____________________

Rock Cycle Diagram