Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Minerals are NEAT!
Document related concepts
Transcript
Overview 3rd and 4th nine weeks Geology (study of Earth) Minerals Rocks Plate Tectonics Earthquakes Volcanoes Earth’s History and Fossils (evolution) Minerals Chapter 3 (orange book) Chapter 4 (green book) Definition A 1 naturally-occurring, 2 inorganic 3 solid with a 4 definite chemical composition. Study of: Mineralogy Branch of: Geology (study of the Earth) Definition/Rules (please consult notes) 1. If we melted sulfur, would it be a mineral? If Calcite had a chemical composition of CaCO2, would it be a mineral? If we made a diamond with PERFECT cleavage, would it be a mineral? If a fossil had a hardness of 11, would it still be considered a mineral? 2. 3. 4. How many known minerals are there? 2000? 3000? 4000? 6000? 4,900 known mineral species – according to wikipedia.com 4,349 Total Valid Species - International Mineralogy Association 6,293. The official list of mineral names, updated in 2009, comprises 6,293 minerals. This list, published by the Commission on New Minerals Nomenclature and Classification (CNMNC), includes not only approved minerals, but also hypothetical, questionable, discredited and unofficial minerals. The number of known minerals grows every year ‘“ according to a CNMNC annual report, about 60 new-mineral proposals are analysed each year. Over 3000 identified minerals (according to textbook) Made of elements, which can be found on the periodic table - pg. 61. Example: 1. Silicates are made of silicon and oxygen, chemical formula of SiO2 2. Halite made of sodium and Chlorine, chemical formula NaCl 3. Pure elements – sulfur, copper, gold, silver, etc. Minerals make up rocks Example: Granite is made of quartz, mica and feldspar Let’s Review what we know… How many minerals exist on Earth? How many “common” minerals are found on Earth? What four characteristics do all minerals share? What are minerals made of? What do minerals combine to form? Let’s look at the three groups of minerals… Groups of Minerals – open to page 88 Silicates: 1. 2. 3. minerals made ofSilicon & Oxygen(SiO2) Quartz - SiO2 Feldspar - KAlSi3O8 Anthophyllite - (Mg,Fe)7Si8O22(OH)2 Carbonates: Carbonate minerals are those minerals containing the carbonate ion: CO3 1. Calcite 2. Dolomite Evaporites: Minerals that are formed from ions in solution being left behind as water evaporated 1. Halite 2. Gypsum What two elements are most common in the Earth’s crust? Therefore, what mineral family do you think is most abundant? What two minerals do you think are two of the most common in the Earth’s crust? Tables at bottom of page 88 Advanced Lab Report – Written Lab Report Introduction & Conclusion For each station: Define the physical, chemical or special property from that station Describe procedure you used and lab equipment at that station Describe very specific results – data table if necessary Address questions from Standard Lab Report (use it as a skeleton for your report) Mineral ID Lab – Purpose: We will be identifying minerals by testing minerals’ physical properties We will also be using: Observations Chemical Properties Special Properties Subjective – opinion, sometimes difficult to classify. Objective – numeric – can not be argued Physical Properties 1. Color - unreliable in identifying minerals *Observation/Appearance is often times NOT enough to identify a mineral – we need to test other physical properties. (1.) Color – reliable? Calcite See why testing other physical/chemical properties is necessary! Pyrite Nearly 300 color variations of diamonds! Reliable colors In a select few minerals, such as sulfur and olivine, color IS a reliable indicator. (2.)Luster- the way a mineral reflects light Two main types of luster: 1. Metallic – looks shiny 2. Nonmetallic Dull, Earthy, Pearly, Vitreous, Gumdrop, Glassy, Silky, Resinous, Greasy/Oily (3.) Streak The color of a mineral in powder form We use an unglazed porcelain plate to test for streak What if the mineral shows no streak? More reliable or less reliable than color? Be able to name minerals that display the same, and different color/streak combinations. (4.) Hardness How easily a mineral can be scratched Whose hardness scale did we use? Moh’s Scale of hardness – pg. 91 Hardest and softest? We will use: Fingernail - 2.5 Glass - 5.5 Streak plate – 6.5 (5.) Cleavage and Fracture Determined by internal, atomic arrangement Cleavage - to break along a flat surface Fracture - to break along a jagged surface Can a mineral have both? Cleavage Fracture Conchoidal fracture is a curved breakage (6.) Acid test – identifying Carbonates Calcite (CaCO3) reacts with hydrochloric Acid HCl (lower case L, not an i) CaCO3 + HCl ---> CO2 + H2O Actual: CaCO3(s) + 2 HCl(l) → CaCl2(l) + CO2(g) + H2O(l) Reaction shown by “effervescence” Example of a chemical property Safety procedures necessary at this station Effervescence (7.) Specific Gravity Specific gravity is the ratio of the density of a substance to the density of water Density = mass/volume Density of a solid: grams/cm3 Density of a liquid: grams/mL 1 cm3 = 1 mL Specific Gravity of 19.28 means it is 19.28 times more dense than the same volume of water. Special Properties – pg. 94 Taste – Halite Odor – sulfur Magnetism – magnetite Double refraction – Icelandic Spar Calcite Fluorescence Effervescence –carbonates (calcite & dolomite) Double Refraction Fluorescence Crystal Size In minerals formed from magma, crystal size indicates the speed the magma/lava cooled (solidified). Large crystals – slowly Small crystals – quickly No crystals – very quickly Lab Safety Hydrochloric Acid Use one drop of HCl Goggles are mandatory Clean minerals after use Keep station clean/dry Hardness station - glass plate remains on lab table No licking minerals at any other station than “taste”. Wash minerals when you’re done. Pick up and replace ONE mineral at a time Know these minerals!!! Diamond - hardest mineral Talc - 1 on Moh’s scale Sulfur - example of odor & reliable color Calcite - reacts with HCl Halite - (NaCl) taste Pyrite - (fool’s gold) color/streak Magnetite - displays magnetic characteristics Icelandic Spar Calcite – Double Refraction Your birthstone How do we get and use Minerals? Mine the ore A mineral is an ore if it can be mined at a profit Processed and sometimes smelted Refine and purify the ore Gems often need cut/polished Smelting To melt (ore) in order to separate the metal contained The ore and the valuable mineral must have different melting temperatures Smelting Do not confuse smelting with smelting (catching small fish called smelt) Gems or gemstones Rare and beautiful minerals Special varieties of another mineral Examples of gems and their common mineral forms are: Topaz --> Topaz Ruby --> Spinel Emerald --> Beryl Sapphire --> Quartz Amethyst--> Quartz Precious Minerals: diamond, ruby, sapphire and emerald, (pearl) (amethyst) Semiprecious Minerals – garnet, tanzanite, fine tourmaline, spinel, and aquamarine, Uses of minerals and gems Diamonds - cutting, saw blades, drill bits Quartz – electronics, time pieces, computers, semiprecious gemstone Gems - jewelry, valuable Some ore minerals often contain valuable elements From these minerals we get aluminum, titanium, zinc, etc. Graphite - pencils, lubricant Gypsum - wallboard, cement Sulfur – fireworks, weapons Other Uses for Minerals Corundum – used for abrasives Bauxite – aluminum ore Halite – food seasoning and preservation Talc – paper, ceramics True or False A diamond will leave a WHITE streak on a streak plate. A gem is plentiful and ugly! The streak plate we used in class is a glazed porcelain plate Since gypsum has large crystals, it probably formed by cooling slowly. A mineral is always organic. Review: The formula for the calcite reaction Native minerals– what are these?
