Minerals+and+Rocks+(chapters+2-3)

=Unit 2: Physical Geology: Minerals and Rocks (chapters 2 & 3)=

Essential Questions:
Earth Science: 3.2, 3.6, 3.7
 * 1) ==How does the Rock Cycle work?==
 * 2) ==Why is the type of bond formed between elements important?==
 * 3) ==How can isotopes be used in radioactive dating?==

=Question of the Day. What is an Element?=
 * Pure, single substance that cannot be broken down into simpler substances by chemical or physical means.
 * Periodic Table of Elements represents one atom of each element and is organized rows based upon similar properties.
 * 90 elements are said to be natural, found in nature where as the rest are synthetic elements, made by scientists.
 * Metals, Nonmetals, Noble Gases, Transitional Metals are the groups of elements.
 * Atomic number is the number of protons(electrons) in an element. It is always a whole number. (ie: 1, 25, 100)
 * Group number above each column of elements relates how many valence electrons the element has. (ie: IIIA, VIA, VIIIA)
 * Mass number (aka atomic weight or atomic mass) is simply the total of protons and neutrons in the element.
 * Symbol is used to represent the element. Usually begins with the first letter of the element's name but some take the Latin root/name. First letter of the symbol is always capitalized and any additional letters are lowercase. (ie: Ca, Na, Li)
 * Atoms are the smallest particle of matter that retains the essential characteristics of an element. They are made up of subatomic particles called protons, neutrons, and electrons.
 * Protons are a positive charge and are located in the nucleus of an atom.
 * Neutrons are a neutral charge and are located in the nucleus of an atom.
 * Electrons are a negative charge are are located in the energy levels outside the nucleus. First level can house 2 electrons. Second level 8, Third level 8, Fourth Level 16...
 * Valence electrons are those electrons in an energy level that is the furthest from the nucleus. These electrons are responsible for forming bonds with other elements.
 * Energy level with 8 in its outer level is said to be stable (have a stable configuration) with the exception of Helium. Helium is stable with only 2 electrons in its outer energy shell.
 * Isotopes are versions of a stable atoms with different numbers of neutrons than it's stable state. For example, Carbon has 3 isotopes: Carbon 12, Carbon 13, and Carbon 14. Carbon normally has roughly 6 neutrons but with the additional neutrons you can get the different types of Carbon isotopes.
 * [[image:carbon-isotopes.png width="512" height="512"]]
 * Some isotopes have an unstable nucleus which means the isotopes disintegrates through radioactive decay. Radioactive decay is measurable and is used to date fossils, rocks and minerals.
 * [[image:radioactive diagram.jpg align="center"]]
 * Half-life is the amount of time it takes a radioactive isotope to degrade half of its parent material.
 * [[image:half-life.jpeg width="388" height="309" align="center"]]
 * Elements bond to form compounds. Compounds are comprised up of 2 or more elements chemically combined. Elements not found in the Noble Gas group (VIIIA) are reactive and form bonds with other elements to reach stable configuration.
 * Chemical bonding is the transfer or sharing of electrons to obtain stable configuration. There are single bonds (where one pair of electrons are involved), double bonds (where two pairs of electrons are involved) and triple bonds (where three pairs of electrons are involved).
 * Ionic bonds form between ions (charged particle) that transfer electrons. This is normally seen between metals and nonmetals. Ie: Sodium + Chloride= Sodium Chloride
 * Covalent bonds form when electrons are shared. Ie: 2 Hydrogen + Oxygen= Water
 * Covalent bonds form when electrons are shared. Ie: 2 Hydrogen + Oxygen= Water

Minerals

 * Geologist define a mineral based upon its characteristics.
 * Naturally Occurring (formed by natural geological processes)
 * Solid
 * Crystalline structure (atoms arranged orderly and repetitively)
 * Chemical composition
 * Inorganic
 * Crystalline structure and chemical composition of minerals give minerals their physical and chemical properties. Physical properties are the easiest to determine.
 * Primary Physical Properties
 * Optical
 * __Luster__: appearance or quality of light reflected from the surface of a mineral
 * metallic luster...have appearance of metals regardless of color
 * submetallic luster...dull/tarnished coating of some metals like native copper or galena so not as shiny as freshly broken surfaces
 * nonmetallic luster...glassy or vitreous, dull or earthy (appearance like soil), pearly, silky (appearance like a satin cloth) or greasy (appears coated in oil).
 * [[image:luster.gif width="432" height="762"]]
 * __Ability to Transmit Light__
 * opaque means object can't transmit light
 * translucent means light is transmitted through object but not an image
 * transparent means light and an image are visible through the object
 * [[image:transmission of light.jpeg]]
 * __Color__
 * Not a good indicator for an mineral since mineral colors can be altered by heat, impurities, natural elements. For example: Quartz can come in tints of pink, purple, white, clear, yellow, gray, and black.
 * __Streak:__ color of powdered mineral left behind on a streak plate.
 * streak color is obtained by rubbing mineral along a piece of unglazed porcelain. Streak color does not vary like color of a mineral does.
 * metallic minerals have a dense, dark streak.
 * nonmetallic minerals have a light colored streak.
 * [[image:streak.jpeg]]
 * Crystal Shape or Habit: responsible for how a mineral will break long planes.
 * equant or equidimensional
 * bladed
 * fibrous
 * tabular
 * prismatic
 * platy
 * blocky
 * botryoidal
 * [[image:crystal_habit_main.jpg width="480" height="104"]]
 * [[image:crystals2.jpg width="497" height="136"]]
 * Mineral Strength
 * __Tenacity__ : minerals toughness or resistance to breaking or deforming
 * brittle, malleable, sectile, elastic
 * __Hardness:__ minerals resistance to being scratched or abraded.
 * Mohs scale rates minerals from a hardness of 1 to a hardness of 10. Diamond is a rating of 10 whereas Talc is a rating of 1.
 * To determine the hardness, take the unknown mineral and rub it against a known hardness (fingernail-2.5, copper penny-3.5, wire nail-4.5, glass and knife blade-5.5, streak plate 6.5)
 * [[image:mohs en.jpg width="420" height="279"]]
 * Cleavage: minerals break along planes of weak bonding producing flat surfaces.
 * Breaking evenly in more than one direction, cleavage is the number of cleavage directions and the angle(s) at which they meet
 * [[image:cleavage.jpg width="439" height="508"]]
 * __Fracture__: minerals break along bonds of equally or nearly equal strength.
 * irregular fracture: uneven surfaces
 * conchoidal fracture: smooth, curved surfaces
 * Splintery fracture: produces splinters
 * Fibrous fracture: produces fibers
 * Density and Specific Gravity
 * __Density__ is mass per unit volume (m/v) and is usually expressed in grams per cubic centimeter.
 * __Specific gravity__ is a unitless number representing the ratio of a mineral's weight to the weight of an equal volume of water. MOst common-rock forming minerals have a specific gravity between 2 and 3.
 * Secondary Physical Properties
 * taste, feel (soapy or greasy), streak smells like rotten eggs, magnetic, double refraction, fizzes when diluted HCl is added
 * 2 types of Mineral Groups
 * Few minerals make up the crust so these are referred to as Rock-Forming Minerals. 8 of the elements found in Rock Forming Minerals are Oxygen (O), Silicon (Si), Aluminum (Al), Iron (Fe), Calcium (Ca), Sodium (Na), Potassium (K), and Magnesium (Mg). Oxygen and Silicon are the most common elements and make up Silicates, which account for 90% of the minerals found on earth. Nonsilicates have economic value like with Iron (Fe) and Aluminum (Al), Gypsum and Copper. Nonsilicates include carbonates, sulfates, and halides that are found in sedimentary rocks.
 * Silicates
 * structure and chemical composition indicates how it formed.
 * All have a tetrahedron structure. Silicon atom surrounded by 4 Oxygen atoms. Tetrahedron can have sheets or chains attached to the oxygen. Some of the Primary elements found attached to the tetrahedron's are Iron (Fe), Magnesium (Mg), Potassium (K), Calcium (Ca), and Sodium (Na).
 * Types of silicates
 * Feldspars (Potassium or Plagioclase): make up 50 % of crust. Produces 3D structure
 * Quartz: only Silicon and Oxygen composition. Produces 3D structure
 * Olivine: produces independent structures
 * Pyroxene (Aguite): produces single chain structures
 * Amphibole (Hornblende): produces double chain structures
 * Micas (Biotite or Muscovite): produces sheets
 * [[image:silicates2.jpg width="480" height="361"]]
 * Nonsilicates
 * 8 % of the crust is made up of nonsilicates. Gypsum, calcite, and halite are found in sedimentary rocks.
 * Types of nonsilicates
 * Carbonates: Positive Ion (metal) added to a Carbonate molecule.
 * Sulfates: Positive Ion (metal) added to a Sulfate molecule.
 * Halides: Positive Ion (metal) added to a Cl, F, or B atom.
 * [[image:nonsilicates.jpg width="400" height="300"]]
 * Mineral Resources are identified deposits that can produces large quantities for extraction. Ores are metallic minerals that can be used for profit. Gemstones can be precious or semiprecious.
 * [[image:gems.JPG width="392" height="607"]]

Rocks

 * Combination of different minerals that undergo processes to change from one type of rock to another type of rock. Can give information as to the environment in which the rock formed.
 * Rock Cycle illustrates the origin of the three basic rock types found on Earth and the interrelatedness of Earth materials and processes. Cycle has alternative pathways.
 * Crystallization is the process of magma/lava cooling to form crystals, which make up igneous rocks.. The rate of cooling (fast/slow), the composition of the magma/lava and the amount of dissolved gases all influence crystallization.
 * Lithification is the process by which sediments are compacted and cemented to form sedimentary rock.
 * Metamorphism is the process by which rocks are changed/altered by pressure and heat into a totally different rock chemically. This forms metamorphic rocks.
 * [[image:TGA002t.jpg width="560" height="420"]]
 * 3 basic groups of rocks found on Earth.
 * **Igneous Rocks**: //Iginis// means fire. So these rocks have formed from magma (molten rock created by the melting of rock in the Earth's mantle and lower crust) or lava (molten rock that is at the earth's surface).
 * Extrusive Igneous rocks are also known as Volcanic Rocks because these rocks form at the earth's surface and are usually made up of lava. The western portion of America is where we would find a large concentration of extrusive rocks along with many oceanic islands.
 * Intrusive Igneous rocks are also known as Plutonic Rocks because these rocks form within the earth and are only exposed to the earth's surface due to uplifting and erosion of layers of earth.
 * [[image:TGA009t.jpg width="480" height="360"]]
 * Igneous rocks are classified based upon their texture and their composition.
 * Texture deals with the overall appearance of the rock based upon the size, shape and arrangement of crystals. It reveals the environment in which the rock formed.
 * Fine-grained are where crystals are too small to be seen with the unaided eye. These rocks usually cool fast hence the small sized crystals. Rhyolite is a fine-grained texture.
 * Coarse-grained are where the crystals large enough to identify the type of mineral with the unaided eye and the size of the crystals are roughly equal to each other. Granite is an example of a coarse-grained texture.
 * Porphyritic are where there are large crystals embedded in a matrix of smaller crystals. This happens because the materials within the magma cool at different rates giving some small and some large sized crystals.
 * Glassy is when there are no crystals present in the rock due to extremely cooling. Some rocks can be considered compact glass, ie. Obsidian, whereas some are frothy glass due to large quantities of gas escaping, ie. Pumice.
 * [[image:TGA022t.jpg width="480" height="360"]]
 * Composition of igneous rocks are mainly composed up of silicate minerals. Therefore Silicon and Oxygen are found in all igneous rocks along with Al, Ca, NA, K, Mg, Fe. Dark silicates are rich in Fe and/or Mg and are low in Silica. Whereas light silicates are rich in K, Na, Ca and are high in Silica.
 * Granitic (Felsic) rocks are rocks that are almost entirely made up of light-colored silicates.
 * Andesitic (Intermediate) rocks are rocks that have a combination between granitic and basaltic, therefore have both light and dark-colored silicates present.
 * Basaltic (Mafic) rocks are rocks that contain large amounts of dark-colored silicates.
 * Ultramafic rocks are rocks that are mostly dark-colored silicates like olivine and pyroxene.
 * [[image:whs-earthscience/TGA021t.jpg width="400" height="300"]]
 * Bowen's Reaction Series shows the order in which minerals crystallize based upon cooling temperatures.
 * [[image:TGA025t.jpg width="480" height="360"]]
 * **Sedimentary Rocks:** //Sedimentum// means settling and Sedimentary rocks are composed up of sediments that have settled in a location. Sediments are weathered materials that are transported by wind, water, waves, gravity, or glaciers. Lithification is when these sediments are compacted and cemented into a sedimentary rock. Sedimentary rocks can tell geologists about Earth's history and past environments because layers of sediments (called strata or beds) can contain fossils. Some sedimentary rocks are important economically such as coal.
 * [[image:TGA079t.jpg width="480" height="360"]]
 * Detrital Sedimentary rocks are made up of solid particles that have come from igneous, metamorphic and other sedimentary rocks. The particles are known as detritus. Size of particles is used to identify detrital sedimentary rocks.
 * Coarse texture is for particles over 2 mm. Common rock with rounded particles over 2mm is known as Conglomerate.
 * Medium texture is for particles that are from 1/16 to 2 mm. Usually sand-sized particles. Common rock is Sandstone.
 * Fine texture is for particles that are from 1/16 to 1/256 mm. Usually silt-sized particles. Common rock is Siltstone.
 * Very fine texture is for particles that are less than 1/256 mm. Usually clay/mud sized particles. Common rock is Shale.
 * Chemical Sedimentary rocks are rocks that are mainly produced by material from chemical weathering or indirectly through life processes of water-dwelling organisms. For example, when water evaporates, minerals are left behind. These precipitates form sedimentary rocks. Chemical rocks can be made up of Calcium Carbonate, Quartz, Gypsum, Halite, or plant fragments. Some chemical rocks are coal, rock salt, flint, and chalk.
 * [[image:TGA062t.jpg width="480" height="360"]]
 * **Metamorphic Rocks:** The changing of a rock by use of heat, pressure, and chemical changes is known as metamorphism. Metamorphic rocks are rocks that have been altered/changed due to metamorphism from igneous, sedimentary, other metamorphic rocks into a new metamorphic rock. Low-grade metamorphism is when slight changes happen to form the rock while High-grade metamorphism is when there are substantial changes to form the rock. For example, Shale, which is a detrital sedimentary rock, will undergo slight temperature/pressure changes to form the metamorphic rock, Slate. This is low-grade metamorphism. High-grade metamorphism will completely erase any bedding planes, fossils or vesicles found in rocks. This happens when there is extreme pressure and high temperatures. Metamorphic Rocks can be classified based upon their texture and mineralogy.
 * . [[image:whs-earthscience/TGA067t.jpg width="480" height="360"]][[image:whs-earthscience/TGA072t.jpg width="480" height="360"]]
 * Foliated texture is when minerals will recrystallize in the perpendicular to the amount of stress (pressure) applied to it. This results in giving the rock a layered or banded appearance. Basically this makes the rock's minerals align parallel to each other.
 * Nonfoliated texture is when minerals are not aligned parallel to each other. Usually the rock is only comprised up of one type of mineral. Example is Marble. It is made up of pure limestone that has only the mineral calcite in it.When metamorphosed, the small Calcite crystals become large interlocking crystals.
 * [[image:TGA070t.jpg width="560" height="420"]]
 * [[image:TGA070t.jpg width="560" height="420"]]
 * [[image:TGA070t.jpg width="560" height="420"]]