Geology 12 with Key

**GEOLOGY 12** **CHAPTER 2** **LAB EXERCISE TWO** **FOLLOW-UP QUESTIONS** Answer the following questions on a separate piece of paper. 1. If you found an unknown mineral, what procedure would   you follow to identify it?   * **Color, luster, streak, hardness, cleavage, fracture, and special properties** 2. If a mineral has no streak, is it metallic? Explain. * **No, only metallic minerals have a streak.** 3. Can a nonmetallic mineral have a streak? Explain. * **Yes, some nonmetallic minerals can have a streak, such as sulfur.** 4. Will a quartz crystal scratch glass? diamond? your fingernail? * **Yes, yes, no** 5. Will calcite scratch glass? gypsum? your fingernail? * **No, yes, no** 6. Will biotite scratch muscovite? Explain. * **Yes, biotite has a higher hardness.** 7. What mineral was used to make your favorite glass beverage mug? * **Quartz** 8. What mineral was used to make your favorite ceramic beverage mug? * **Feldspar** 9. The minerals calcite, halite, and gypsum are nonmetallic, light, softer than glass, and have three directions of cleavage. * a. Give two ways calcite differs from halite: **Calcite fizzes   with acid, double refraction** * b. Give two ways halite differs from gypsum: **Halite tastes salty, is cubic** * c. Give two ways calcite differs from gypsum: **Calcite fizzes with acid, double refraction** * d. What is the economic significance (use) of calcite? **Cement, lime** * e. What is the economic significance (use) of halite? **Salt, food, roads** * f. What is the economic significance (use) of gypsum? **Wallboard, cement** 10. What products in your house might be made from these minerals? * a. mica: **Electronics, paint** * b. gypsum: **Walls** * c. hematite, magnetite, or limonite: **Cars, flatware, machinery** * d. graphite: **Pencils, dry lubricant** * e. galena: **Batteries, protective coatings in planes, TV, dentist tools** * f. feldspar: **Glass, ceramics, fertilizer** 11. You are given three minerals: a dark plagioclase feldspar, pyroxene (augite), and amphibole (hornblende). * a. List four physical properties these three minerals have in common: **Color, hardness, cleavage, density** * b. What property best distinguishes amphibole from the pyroxene and the plagioclase feldspar? **Cleavage** * c. What property best distinguishes pyroxene from the plagioclase feldspar?   **Color, luster, maybe form** 12. You are given a specimen of orthoclase (K) feldspar and one of light plagioclase (Na/Ca) feldspar. * a. List four physical properties these two minerals have in common: **Color, hardness, cleavage, density** * b. List one physical property that can be used to best distinguish orthoclase from plagioclase. **Color, luster, maybe form** **GEOLOGY 12** **CHAPTER 2 WORKSHEET** **MINERALS AND ROCKS** 1. An atom is the smallest particle into which an element can be subdivided and still retain its distinctive chemical characteristics. 2. Atoms of the same element which have different atomic mass numbers are known as isotopes. 3. A positively charged atom is called a(n)   ion (cation). 4. A negatively charged atom is called a(n) ion (anion). 5. In a covalent chemical bond, atoms share electrons. 6. Synthetic gemstones are not true minerals because they are not naturally   occurring. 7. When a mineral composition includes elements in a compositional range, those elements can interchange in the mineral's structure because the elements have a similar size and charge. 8. In order for crystals of a given mineral to form, there must be time for the atoms to arrange themselves into a   regular internal structure. 9. A glass may be described as a solid which cools so rapidly from a liquid that the atoms remain randomly arranged in a noncrystalline form. 10. The two fundamental characteristics of a mineral which will distinguish it from all other minerals are its composition and its internal structure. 11. Diamond and graphite, which have the same composition but very different crystal structures, are examples of   polymorphs. 12. Hardness is the ability of a mineral to resist scratching. 13. The tendency of a mineral to break preferentially along planes of weakness is called   cleavage. 14. Gold can easily be distinguished from pyrite on the basis of its specific gravity, another physical property of minerals. 15. Streak,   the color of the powdered mineral, is more consistent than the color of a bulk mineral. 16. The largest mineral group in the earth's crust is the silicates group. 17. Pyroxenes and amphiboles are two types of chain silicates, in which silica tetrahedra share oxygen atoms in only one dimension.