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Name: _____________________________________ Color: _______ Date: _______________________ Earth Science – Mineral Chemistry and Mineral Identification Notes I. What is a mineral? A mineral must be all of the following: 1. ____________________ occurring 2. Inorganic (not living) 3. Definite _______________________________________ ( ___________________ is a solid in which the atoms are arranged in __________________ patterns.) 4. Definite ______________________ (what it’s made of) 5. An element or ______________________________ (never a mixture) II. Elements in Earth’s Crust Using the slide, label the top 4 elements found in Earth’s crust on the pie chart. Which 2 are the most abundant? Oxygen Silicon Aluminum Iron Calcium Sodium Potassium Magnesium Other III. Mineral Composition A. ________________ (Si & O) – consists of ____ oxygen atoms packed closely around a single silicon atom. This group is the most common! Why?_______________________________________________ B. _____________________ (C & O) C. _____________________ (S, but no O) D. Other (such as diamond, graphite made of only one element) IV. How do minerals form? – 3 ways A. Molten rock (lava or magma) solidifying (igneous minerals) B. Precipitating from water saturated with ions (can be due to evaporation) (sedimentary) C. Metamophosing (increased temp. and pressure) of other minerals (metamorphic) V. Mineral Crystal Size A. Small Crystals – indicates _______ cooling of molten rock B. Large Crystals – indicates ________ cooling of molten rock VI. Mineral Characteristics used for identification A. _______________ – the first property you notice – this is usually the 1st step in identification, but the least useful B. _______________ – the way light reflects from a minerals surface – 2 types 1. ___________________ – shiny and looks like a metal (silver, gold) 2. __________________________ – glassy, brilliant, greasy, oily, waxy, silky, or pearly C. ______________ 1. Light (white, light gray, pink, orange, light blue, light purple) 2. Dark (black, dark gray, dark blue, most greens, especially dark) D. ________________ – the color of the ________________ left when a mineral is rubbed against a hard rough surface (usually unglazed porcelain- ceramic tile) *can be a different color than mineral Examples: pyrite (fool’s gold)- color gold, streak green-gray streak Hematite- color silver or red-brown, red-brown streak E. ______________________ – is a mineral’s resistance to being scratched Use Moh’s Scale of Hardness 1. Scale ranges from ____ to _____ 2. _____ is softest & _____ is hardest 3. Factoid – What is the hardest substance on Earth?? __________________ F. ______________ _______________ – comparing density of a mineral to the density of water G. ________________ – tendency of a mineral to break along smooth surfaces in particular directions a. determine if cleavage is present b. # of cleavage directions (parallel sides count as one direction) c. if 2 or more cleavage directions, determine if the angle between them is =90 degrees or not H. __________________________ – degree to which light can pass through a mineral in a thin slice a. transparent (most light) translucent opaque (NO light) I. Special Properties – a. Acid reaction – some minerals give off CO2 (carbon dioxide) when acid is added i. Fizzes a lot: calcite ii. Fizzes a little, or a lot if mineral is powdered b. ____________ – example: salty taste of halite (NaCl) c. ____________ – example: graphite is slippery and marks paper d. Magnetic: magnetite, ilmenite e. Conchoidal fracture: looks like a rainbow: indicates quartz f. Double refraction: ____________ splits light into two rays (evidence: a dot becomes two dots if viewed through calcite) WHAT WAS THE MINERAL WE BROKE IN CLASS? ________________________ EVIDENCE?___________________________________________________________________________ _____________________________________________________________________________________ Minerals and Graphing Graphing 10 9 8 7 6 5 4 3 2 1 0 Gypsum Hardness Feldspar Corundum 1. Which is the softest mineral? 2. Which is the hardest mineral? 3. Which mineral is closest in hardness to gypsum? 4. Which mineral is closest in hardness to feldspar? 5. Which mineral is farthest in hardness from diamond? 6. Which mineral (or minerals) can scratch feldspar? 7. Which mineral (or minerals) can scratch corundum? 8. Which mineral (or minerals) can scratch talc? 9. Which mineral (or minerals) can scratch gypsum? 10. Which mineral (or minerals) can scratch diamond?