Name ____________________________ Date _______________ Minerals 1. What is a Mineral? A mineral is: a. naturally occuring b. inorganic c. solid d. has a crystal pattern e. definite chemical composition and physical properties 2. Covalent bonds are bonds between atoms that are held together by the sharing of electrons . Covalent bonding is common between nonmetals. Ex) CO2, SiO4, NH4, and H2O a. The goal of all atoms is to look like a noble gas. GOAL: SHARING: 3. Ionic bonds are bonds between atoms that are held together by the transferring of electrons. Ionic bonding is typical between metals and nonmetals. Ex) NaCl, LiF, and KBR (salts) a. Stealing an electron is better than sharing. Once an atom loses or gains an electron, then it is now called an ion. b. Ions (ionic) act like magnets, and have a strong bond. STEALING (transfer): 4. Metallic bonds are bonds between metals atoms that are held together by freely moving electrons. This is why copper (metal) wire is used in the transfer of electricity (electrons). 5. Mineral formation occurs in a. lava and magma b. evaporating liquids c. changes due to heat and/or pressure 6. Crystal Structure a. Crystals are minerals whose atoms are arranged in a regular pattern. Ex. diamonds, halite (salt), and quartz b. Types of crystals: 1) Cubic (also called isometric) - halite, diamonds 2) Orthorhombic - sulfur, topaz 3) Tetragonal – chaclopyrite 4) Triclinic – turquoise 5) Monoclinic – gypsum, borax, sugar (not a mineral) 6) Hexagonal - quartz, graphite, calcite 7. The Silica Tetrahedron (plural = tetrahedra) a. Silicates are compounds with the elements, silicon and oxygen, plus one or more metals. b. More than ninety percent of the minerals in Earth’s crust are silicates. c. The silica tetrahedron is the basic unit of silicates with one silicon atom having covalent bonds with four oxygen atoms. 4 oxygen atoms silica tetrahedron: A small silicon atom hidden in the middle of the oxygen atoms (a good fit) 8. Arrangements for Silica Tetrahedra a. Single tetrahedra – Individual silica tetrahedra ionically bonded with iron and magnesium atoms. Ex. olivine b. Single chains – Chains of tetrahedra by covalently bonding two of the four oxygen atoms with other tetrahedra. Chains are ionically bonded together with metals. Ex. pyroxene c. Double chains – Chains of tetrahedra by covalently bonding two and three of the four oxygen atoms with other tetrahedra. Ionically bonded with metals. Ex. Hornblende (amphibole) d. Sheets – Sheets of tetrahedra by covalently bonding three of the four oxygen atoms with other tetrahedra. Ionically bonded with metals. Ex. mica e. Network of tetrahedra – All four oxygen atoms are covalently bonded with other tetrahedra. Ex. Quartz, feldspar Resources and Mineral Identification I. Using Resources 1. Most of the metal in furniture, vehicles, and buildings is iron or steel. These metals originally come from ore. a. An ore is a mineral from which a metal or nonmetal can be extracted profitably. Copper and aluminum ores are some examples. 2. Coal and petroleum products are used as fuels, as well as in the manufacture of plastics, medicines, paints, and cosmetics. Glass is made from _sand . 3. Sand and gravel are used to make roads, and we combine them with limestone to make concrete. 4. The amount of mineral resources is limited. II. Minerals 1. A mineral is a naturally occurring inorganic solid with well-defined physical and chemical properties. a. Some minerals are chemical elements or compounds, such as diamond (C) and quartz (SiO2). 2. Rocks are formed from one or more minerals. 3. Although thousands of minerals have been identified and classified, less than a dozen are commonly found. Clay, feldspar, quartz, and clacite make up the bulk of rocks found near Earth’s surface. 4. Oxygen and silicon make up ____half___ of the _____mass_____ of these minerals. III. Identifying Minerals Geologists usually identify minerals on the basis of their _____physical___ and _______chemical________ properties. 1. Color - ____least reliable_______ a. Many minerals have a characteristic color, but because of _____impurities_____, colorless and white minerals are often _______discolored_________. 2. Luster - ____metallic or nonmetallic_____ a. Luster describes the way light is ______reflected_______ from the freshly cut surface of a mineral. b. Minerals with a ______metallic_____ luster have a hard, shiny look like polished metal. This is because light is unable to penetrate the surface and almost all the light is __reflected__. Non-metallic luster = _not all light is reflected_______. 3. Streak a. The test for streak is performed by _____rubbing____ a fresh corner of the mineral across a white, unglazed streak plate. The streak is a __powdered____ form of the mineral. 4. Crystal Structure a. A crystal is a ______regularly_______ shaped ____solid_____ formed by an ordered pattern of _____atoms_______. 5. Hardness a. Minerals differ in hardness. You test for hardness by ____scratching_____ the unknown mineral with the edge or point of other minerals of known _____hardness_____. b. The geologist Friedrich Mohs created a _____scale____ of hardness that uses relatively common minerals. On the Mohs’ scale, talc is the ____softest___ mineral with a hardness of 1, and diamond is the ___hardest_____ mineral, which equals __10_. 6. Cleavage & Fracture a. If a mineral _____breaks____ readily along flat surfaces it shows cleavage. b. Many minerals break along flat surfaces called ____cleavage planes_________. c. Cleavage planes are not always aligned with the sides of crystals. For example, quartz has a six-sided crystal, but it breaks along _________________ surfaces, which is called ________________. 7. Density a. Minerals also vary in density and _______specific gravity___________. Specific gravity is a ratio of the density of a substance to the density of water. b. Water’s density is 1 gm/cm3. Therefore, a mineral with a density of 4 gm/cm3 has a specific gravity of _____four______. This is Moh’s Scale of hardness. It is a relative index based upon the hardness of selected common minerals. 8. Radioactivity a. Minerals, which contain ___uranium___ or ___radium__, are radioactive. These minerals are found with a __geiger___ counter. b. Radioactivity involves the emission of __alpha__, __beta__ particles, and ___gamma___ rays from the atom nucleus. (unstable elements breaking down into more stable elements) c. An example of a radioactive mineral is _____zircon______. 9. Fluorescence a. This occurs in some minerals when they absorb ____ultraviolet_____ light and give off _____visible_______ light. b. If they continue to glow after the black light is turned off it is called _____phosphorescence____________. 10. Magnetic Properties a. Some metal ___ores__ have such a large concentration of ___iron___ in them, that they respond to magnet. b. ___lodestone___, a kind of ___magnetite___, acts as a magnet. 11. Double Refraction a. As light passes through ___calcite__ the light is split into __2_ rays. Therefore two _____images______ are seen. 12. Acid Test a. Only minerals that contain CO3 (__carbonate__) will react to acid. b. The most common mineral of this type is __calcite__, whose formula is ______CaCO3_______. c. When a drop of _____hydrochloric___ acid is placed on the mineral it will _____bubble___ giving off __CO2__ gas. d. There are three rock types that will react with acid due to their large content of ____carbonate____. They are ___limestone___, ____dolomite_____, and ____marble_____. CaCO3 + 2HCl ---> CaCl2 + H 2O + CO2 (Calcite) (Hydrochloric acid) (Calcium Chloride) (Water) (gas bubbles) IV. Practice (refer to pages 11 & 16 of your ESRT’s) 1. What is the most abundance element in the Earth’s crust by mass? a. Sodium c. Aluminum b. Oxygen d. Hydrogen 2. What is the percent by volume of oxygen in the Earth’s crust? a. 78 % c. 94.04 % b. 5.63 % d. 33.0 % 3. Silicate minerals are made of both silicon and oxygen. By using page 11 of your reference tables, why do you think silicate minerals are the most common minerals in the Earth’s crust? __Silicon and oxygen are the most common minerals available_ _______________________________________________ _______________________________________________ 4. Identify the mineral. Luster = nonmetallic, Hardness > 4, shows Cleavage, white to pink Color. ____potassium feldspar_________ 5. Identify the mineral. Luster = metallic, Hardness > 4, shows Fracture, brassy yellow Color. ________pyrite______________ 6. Identify the mineral. Luster = nonmetallic, Hardness < 5, shows Cleavage, cubic and salty taste. ________halite_________________ 7. Identify the mineral. Luster = metallic, Hardness < 4, shows Cleavage, metallic silver Color. _________galena________________ 8. Which mineral is used in drywall? ________gypsum___________________