18.Identify the FALSE statement. Crystals: 19.Which of the following is a mineral? Amber (tree sap)
Sugar (formula C 6 H 12 0 6 ) Coral (from reefs) Ice – fits the mineral definition of criteria; amber, coral, sugar and ivory have organic origins Ivory 20.Which of the following is NOT a mineral? Oil, because it’s an organic liquid, not a solid – minerals by definition must be solid. Also, they don’t have to be rock material. Salt is crystalline. The descriptions of gold and pyrite are correct, but these are not disqualifying reasons. Pyrite, because it’s a chemical compound A gold nugget, because it’s a native metal Glacial ice, because ice isn’t a rocky mineral Salt, because it’s not crystalline 21.Graphite is: Composed of carbon atoms, arranged as tetrahedrons, and held together with strong covalent bonds Harder than glass The polymorph of galena The lead in the pencil you write with – graphite is very soft, pure carbon polymorph of diamond. Its carbon atoms are arranged in sheets, weakly bonded to each other. Pure silicon 22.An unknown mineral scratches glass, and shows no cleavage but does show conchoidal fracture. Which of the following could it be? Talc Quartz – only quartz meets these specifications; talc is too soft, halite and mica have excellent cleavage, and galena has a high specific gravity. Galena Mica Halite 23.An unknown mineral sample can be scratched by a copper penny but will also scratch the penny; it reacts with dilute hydrochloric acid to produce carbon dioxide gas. Which of the following could it be? Calcite Gypsum Talc Fluorite None of the above 24.Window glass is not a mineral because it doesn’t have crystal lattice structure. True
False 25.Snowflakes are a mineral form of water True False 26.Minerals generally can be destroyed by heating, dissolution or other chemical reaction. True – probably every known mineral can be destroyed by heating, dissolution or reaction with specific chemicals. Metamorphism is a process that breaks down nearly all minerals under geologically-occurring conditions of changed temperature, pressure or presence of other chemicals. False 27.Gold, silver, and copper can all be found, naturally, as native metals. True – metals that exist as elements, not compounds, are called native metals; gold and copper are two examples.
- Fall '09
- Plate Tectonics, north american plate, Basalt