4200M2K_F10 - GLY4200C Name 90 points October 28, 2010 16...

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1 GLY4200C Name 90 points October 28, 2010 16 took exam - Numbers to the left of the question number in red are the number of incorrect responses. Instructor comments are in blue . Florida Atlantic University MINERALOGY -- MIDTERM 2 EXAMINATION KEY True-False - Print the letter T or F in the blank to indicate if each of the following statements is true or false. Illegible answers are wrong. (1 point each) 1 T 1. If two ions have a similar radius, the ion with the higher charge enters the crystal structure preferentially. 1 T 2. There is a definite chemical discontinuity between the lower mantle and the outer core. 2 F 3. The symbol [uvw] represents a Miller Index. 1 T 4. All pyramidal forms are open 0 F 5. The symmetry of an octahedron compressed along the z axis will be higher than that of a regular octahedron. 0 T 6. Magnetic separation is used in both laboratory and commercial scales for mineral separation. 1 T 7. Aircraft towing magnetometers are sometimes used for remote sensing of large areas, in the hopes of finding deposits of sulfide minerals, which may be economically valuable. 1 F 8. High-spin Fe 3+ is smaller than low-spin Fe 3+ . 1 F 9. Net magnetic moments are generated only in atoms or ions with complete electronic shells. 2 T 10. The blue color in minerals such as kyanite, glaucophane, crocidolite, and sapphire is the result of a ferric to ferrous charge transfer. 2 F 11. Contact twins have an irregular composition surface separating two individual crystals. 0 T 12. When twinning occurs in minerals of low symmetry, it may cause the mineral to appear to possess more symmetry than it actually does.
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2 2 T 13. A crystal face composed of either all anions or all cations will grow very quickly, often growing itself out of existence. 4 F 14. Complex operations involve a combination of two simple operations, both of which must exist independently. 4 T 15. A rhombohedron is a closed form. 1 T 16. Symbols such as 4/m 3 6 2/m or 3 6 2/m are known as Hermann-Mauguin symbols. 7 T 17. Above the Curie temperature ferromagnetic materials become paramagnetic. 0 T 18. Diamagnetic minerals are weakly repelled from a magnet in the presence of a strong external field. Multiple-Choice - Choose the best response to each statement or question. Print the letter corresponding to your choice in the blank. (1 point each) 3 B 1. In terms of weight per cent, the three most common elements in the earth’s crust are: A. Silicon, iron, aluminum B. Oxygen, silicon, aluminum C. Oxygen, calcium, silicon D. Oxygen, silicon, iron 0 C 2. Trace elements have abundances less what weight percent? A. 0.001 B. 0.01 C. 0.1 D 1.0 3 A 3. In which crystal system does a = b c , " = ( = 90 / and $ = 120 / ? A. Hexagonal
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This note was uploaded on 12/13/2010 for the course GLY 4200c taught by Professor Warburton during the Spring '10 term at FAU.

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4200M2K_F10 - GLY4200C Name 90 points October 28, 2010 16...

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