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3-1 What is a mineral? 3-2 Identifying minerals?

3-1 What is a mineral? 3-2 Identifying minerals?. ( epsomite). {enrich} What is a Mineral?. More than 4,000 minerals (40-50 new minerals identified each year!) but only 100 common minerals about 20 minerals make up most of Earth’s crust

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3-1 What is a mineral? 3-2 Identifying minerals?

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  1. 3-1 What is a mineral?3-2 Identifying minerals? (epsomite)

  2. {enrich} What is a Mineral? • More than 4,000 minerals (40-50 new minerals identified each year!) • but only 100 common minerals • about 20 minerals make up most of Earth’s crust • native elements occur in nature in pure form (ex: gold, copper, diamond, sulfur, graphite, silver, and platinum)

  3. Most minerals are COMPOUNDS… (a chemical combination of two or more elements), while rocks are mixtures of minerals (and sometimes organic matter like shells) • Some minerals are elements (like copper, gold and diamonds)

  4. 95% of the earth’s crust is made of silicates(minerals made of silicon and oxygen): ex: quartz SiO2) sulfide (+ sulfur) ex: cinnabar (HgS) sulfate (+sulfur & O) carbonate (C & O) ex: calcite: CaCO3 oxide (+oxygen) ex: corundum: Al2O3 halide –ex: salt {enrich} Classification of minerals

  5. Inorganic Natural Solid Compound (or element) Crystal system Characteristics of ALL minerals: (INSCC)--foldable--

  6. Inorganic never alive not from something alive rocks can have organic matter Naturally occurring not synthetic or artificial or man-made

  7. Solid at room temperature Chemical composition some single element in pure form (native elements) like copper, diamond, sulfur most are compounds like quartz (SiO2) and cinnabar (HgS) rocks are mixtures Can you read a chemical equation? Crystal system repeating pattern with flat sides (called faces) most are only visible with a microscope

  8. 1--hardness 2--color 3--streak color 4--luster 5--density 6--crystal structure 7--cleavage/fracture 8--special properties 8 ways to test the identify of a mineral

  9. Hardness • how easy is it to scratch the mineral? • Moh’s scale • 1812 by Friedrich Mohs • 1 (talc) - 10 scale (diamond) • common substances: • fingernail=2.5 • penny=3-3.5 • glass=5.5-6 • steel=5-5.5 • streak plate= 6.5-7.5

  10. Colors of QUARTZ

  11. Color easy but not reliable color may change over time some minerals have MANY colors (like quartz)--due to impurities many minerals have the same color Streak Color--practice more reliable than regular color color of its powder use streak plate (unglazed tile) examples: pyrite=black gold=golden, yellow Two colors

  12. Luster how a mineral reflects light from its surface 1. metallic (shiny) 2. nonmetallic: glassy, dull, earthy, waxy, pearly Density mass/volume remains the same (no matter the specimen size) also called “heft” may use “specific gravity” (same as density, but no units)

  13. Types of luster

  14. Crystal System Example: cubic- Example: hexagonal Cleavage/Fracture (paper towel demo) how a mineral BREAKS 1. Cleavage=smooth break 2. Fracture=irregular break—rough, jagged, or curved (most minerals have fracture) quartz=curved, shell-like surface copper and iron=hacky fracture (forms jagged points)

  15. Fluorescence (glow under UV light)--scheelite magnetic--magnitite radioactive--uraninite fizzes (gives off CO2) in acid– calcite (demo) Very malleable (easy to shape)--gold earthy odor--clay soapy feeling--talc feels greasy--graphite double refraction--optical calcite Special Properties

  16. Special Properties:

  17. A rock is a mixture of _____________. • minerals

  18. Mystery mineral game: • Pick a mineral from pp. 800-801 • other classmates must ask yes/no questions to determine the identity of the mystery mineral (like “20 Questions)

  19. Find color and streak color What is the luster? Find the hardness (a range) Find density (use water displacement for volume)—could use “heft” AFTER 2-4 tests are completed, try to identify the mineral, then... Bring the mineral to Mrs. McMullan when finished to see if you are correct and to get another mineral to identify. LAB: What mineral do you have?

  20. Questions for review • Which of the following definitions best describes a MINERAL? • a. a substance that cannot be separated or broken down into simpler substances by chemical reactions • b. a substance made up of atoms of two or more different elements joined by chemical bonds • c. a naturally formed inorganic solid that has a definite crystalline structure • d. a solid whose atoms, ions, or molecules are arranged in a definite pattern

  21. Minerals that contain one or more elements combined with silicon and oxygen are called _________ {enrich} • silicates • Which mineral can be identified by tasting? • halite (salt) • What is the difference between a mineral and a rock? • Minerals are elements or compounds. • Rocks are mixtures (or minerals).

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