Unit II Rocks and Minerals

Earth’s Interior Our Earth consists of four main layers

Earth’s Interior Inner Core- 760 mile radius, consisting of solid iron and nickel and also reaching temperatures close to the Sun’s surface Outer Core- transition layer that still consists iron and nickel yet is a thick liquid layer

Earth’s Interior Mantle- Largest portion of the interior and has the most viscosity (thinnest liquid) Crust- 3 to 40 miles thick and is often divided into two separate layers Continental- Old cratons in which we live and has an average density of 2.7 g/cm^3 Oceanic- Newly created crust along the ocean floor and has an average density of 3.0 g/cm^3

Composition of Earth’s Crust There are 8 elements that make up 99% of the Earth’s Crust 1.Oxygen (47%) 2.Silicon (28%) 3.Aluminum (8%) 4.Iron (5%) 5. Calcium (3%) 6. Sodium (3%) 7.Potassium (3%) 8.Magnesium (2%)

Minerals Minerals- naturally occurring solid; a chemical substance that is formed through geological processes and that has specific characteristics

Minerals Characteristics of Minerals 1.Occur naturally 2.Are solids 3.Definite chemical composition 4.Atoms are arranged in definite pattern 5.Are inorganic

Minerals Is ice considered a mineral, why or why not????

Minerals 1.Occur naturally- as snow, sleet or rain 2.Are solids- Check 3.Definite chemical composition- 2 Hydrogen's and 1 Oxygen (H 2 O) 4.Atoms are arranged in definite pattern- Hexagonal symmetry

Properties of Minerals 1.Crystal Form- How the different components solidified 2.Luster- the quality of light reflected from the surface 3.Color- impurities can make this variable 4.Streak- color of mineral in powdered form Trigonal Hexagonal Cubic

Properties of Minerals Cont. 5. Hardness- classifying according to Mohs scale ( 1 being the softest and 10 being the hardest) 6. Cleavage/Fracture - based on the angle in which the mineral is broken off due to weak bonding planes 7.Specific gravity- the “heft” of the mineral, or how dense the mineral is 8.Other properties- smell, refraction, magnetism, feel, taste, reaction to HCL

Mineral Groups Silicates- Composed mostly of silicon and oxygen and also with one or more metallic element (silicate tetrahedron) Examples: Quartz, Feldspar, Micas, Talc Carbonates - contains CO 3 a salt of carbonic acid. Examples: Calcite, Graphite Halides- contain chloride and flouride ions Examples: Halite and Flourite Oxides and sulfides -are minerals that have metals combined with oxygen or sulfur. Examples: Hematite, Magnitite, Pyrite, Galena, Sulfur

Mohs Hardness Scale 4.5=

Rocks A “rock” can be described as a naturally occurring aggregate - a combination of minerals We find three different types of rocks, they include Igneous Sedimentary Metamorphic.

Rock Cycle

Rocks Igneous- rocks that solidified from magma or lava Metamorphic- rocks that have undergone extreme heat and pressure Sedimentary- the collection or compaction of minerals and/or organic particles

Igneous Extrusive- Formed from lava flows and eruptions from volcanoes –Produces our fine grained and glassy textures –Underwent a fast rate of cooling –(Basalt, pumice, obsidian)

Igneous Intrusive- Formed from magma flows underground –Produces our coarse grained texture –Underwent a slow rate of cooling –(Granite, Gabbro, Diorite)

Sedimentary Clastic- composed of fragments, or clasts, of pre-existing rock Classified by the size of particles –Conglomerate –Sandstone –Mudstone

Sedimentary Organic- fossils that have been cemented together –Coal –Coquina Chemically- have mineral crystals made from elements that are dissolved in water. CaCO3 limestone Coquina

Metamorphic Former Sedimentary or Igneous rocks that have undergone extreme heat and pressure

Metamorphic

Foliated Non-Foliated Foliated rock is a product of differential stress that deforms the rock in one plane Non- Foliated: Rocks that have undergone even more heat and don’t have any structural pattern