- Slides: 36
Minerals and Rocks
Properties of Minerals • • Luster Streak Hardness Cleavage
Properties of Minerals • Luster: the way a mineral shines, or reflects light
Properties of Minerals • Streak: the color of a mineral when it is ground to a powder.
Properties of Minerals • Hardness: the measure of how easily a mineral can be scratched.
Properties of Minerals • Cleavage: is the tendency of a mineral to split easily along flat surfaces. Mica cleaves, or splits, along one plane. Ruby does not split along cleavage planes. Calcite has three cleavage planes.
Uses of Minerals • In glasses( titanium) • In watches (quartz) • In Aluminum bats (bauxite) • In Windows (talc, quartz, calcite, and feldspar • In Plumbing Pipes (copper) • Any many others
Rocks vs. Minerals • Minerals are non living solid materials that has a definite chemical makeup. • What? ? ? • What this means is that each mineral is made up of just one thing. • Rocks are solid materials made up of one or more minerals.
Earth’s Layers • 1 st Layer Crust: the thinnest layer made up of rock • 2 nd Layer Mantle: a thick layer of rock between the crust and the core. • 3 rd Layer Core: a dense ball with a liquid out part and a solid inner part.
Rocks • A rock is a naturally occurring mixture of one or more minerals, organic matter, volcanic glass and sometimes other materials. • Rocks are classified by how they are formed, their composition, and texture • Rocks change over time through the rock cycle
Types of Rocks • Igneous Rocks form when melted rock from deep below Earth’s surfaces cools and hardens. Obsidian forms when molted rock cools quickly. Granite is molten rock that hardens in the crust Basalt makes up much of Earth’s crust beneath the oceans.
Igneous rocks form when magma or lava cools allowing minerals to crystallize. Magma—molten rock material inside the Earth Lava—molten rock material that reaches Earth’s surface. Magma that cools slowly beneath the surface produces Intrusive Igneous Rocks. Lava that cools at the surface produces Extrusive Igneous Rocks.
Intrusive Igneous Rocks Cools slowly = larger crystal grains Granite Diorite Cools quickly = smaller crystal grains Extrusive Igneous Rocks Obsidian Rhyolite Pumice Scoria
Types of Rocks • Sedimentary rock forms when sand, particles of rock, bits of soil, and remains of once-living things (sediments) are pressed together and harden. This only happens when they are weathered down. Conglomerate forms from sediments of different sizes. Shale forms from thin layers of clay. It is smooth and breaks easily into layers.
3 Types of Sedimentary Rock 1. Clastic—made from broken fragments of other rocks 2. Chemical—formed when dissolved minerals come out of a solution 3. Organic—made from remains of once living things
Clastic Sedimentary Breccia is a term most often used for clastic sedimentary rocks that are composed of large angular fragments. The spaces between the large angular fragments can be filled with smaller particles or a mineral cement that binds the rock together.
Chemical Sedimentary Limestone is a sedimentary rock composed primarily of calcium carbonate (Ca. CO 3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters. It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris.
Organic Sedimentary Coal is an organic sedimentary rock that forms from the accumulation and preservation of plant materials, usually in a swamp environment. Coal is a combustible rock and along with oil and natural gas it is one of the three most important fossil fuels.
Processes Needed to Form Clastic Sedimentary Rocks 1. Weathering-breaking of rocks into sediment 2. 1. Erosion- movement of sediment 2. Deposition-settling of sediment in layers 3.
4. Compaction-squeezing of sediment together 5. Cementation-natural gluing together of sediment
§ Sedimentary Rocks are formed at or near the Earth’s surface § No heat and pressure involved § Strata – layers of rock § Stratification – the process in which sedimentary rocks are arranged in layers
Types of Rocks • Metamorphic rock is rock that forms when existing rocks are changed by extreme heat and pressure. Granite, an igneous rock, changes to gneiss. Limestone, a sedimentary rock, changes to marble
Metamorphic Rock • Foliated - contain aligned grains of flat minerals Gneiss is foliated metamorphic rock that has a banded appearance and is made up of granular mineral grains. It typically contains abundant quartz or feldspar minerals.
Metamorphic Rock • Non-Foliated – mineral grains are not arranged in bands or planes. Marble is a nonfoliated metamorphic rock that is produced from the metamorphism of limestone. It is composed primarily of calcium carbonate.
Metamorphic Rock • Determine if the following rock samples are foliated or non-foliated: Amphibolite Quartzite Phyllite Foliated
Foliated Nonfoliated -Grains grow and rearrange but do not form layers. -Grains in parallel layers. -Formed with high pressure -Gneiss -Slate: watertight -Metamorphic rocks -Change in solid state (NO melting). -Marble -Quartzite -Heat and pressure -Formed with less -Classified by texture, and mineral pressure. composition.
The Rock Cycle • The continuous series of changes that rocks undergo.
Rock Foldable: Words you need to know! • • • Rock cycle Igneous rock Metamophic rock Sedimentary rock Intrusive Foliated Extrusive Chemical • • • Weathering Erosion Magma Nonfoliated Compaction Cementation Clastic Organic Lava Deposition
What Do You Remember?
What Do You Remember? • The way a mineral shines is called its __________. • A solid material made up of one or more minerals is ________.
What Do You Remember • How easily a mineral can be scratched is its _________ • Rock that forms from cooled molten rock is called________
What Do You Remember • The color of a mineral when it is ground to a powder is • • A: hardness B: texture C: streak D: cleavage
What Do You Remember • Sand, bits of rock, and the remains of once -living things are called • • A: sediment B: core C: minerals D: metals
What Do You Remember • All rocks are made up of one or more • • A: metals B: minerals C: once-living things D: crystals
What Do You Remember • What is not a property that can be used to help identify a mineral? • • A: luster B: streak C: hardness D: talc