Geology 100: Chapter 3

Which of the following statements is TRUE? A. Helium has an atomic number of 2. B. An isotope of an element has the same atomic mass, but different atomic number. C. The atomic mass of an element is approximately equal to the number of protons in an atom of that element. D. Hydrogen has an atomic mass of 2.

A. Helium has an atomic number of 2.

Which of the following statements about gemstones is FALSE? A. In order to be considered precious or semiprecious, a gemstone must be transparent. B. Many gemstones come from pegmatites, which are particularly coarse-grained igneous rocks. C. A gemstone is a mineral that has value because of its rarity and beauty. D. Ruby is a gemstone variety of the common mineral corundum.

A. In order to be considered precious or semiprecious, a gemstone must be transparent.

Identify the FALSE statement. A. Polymorphs of the same mineral have the same crystal shape because they contain the same basic atoms bonded in the same way. B. Crystals can be a variety of geometric shapes, including cubes, trapezoids, pyramids, octahedrons, hexagons, columns, blades, and needles. C. The faces of a crystal need not be the same size throughout the crystal, but the angle of intersection between comparable faces is the same throughout. D. There is an angle of 120° between each crystal face of the hexagonal column of a quartz crystal.

A. Polymorphs of the same mineral have the same crystal shape because they contain the same basic atoms

When you scrape a mineral along a ceramic plate to observe the color of its powder, you are checking the physical property known as: A. streak. B. cleavage. C. luster. D. specific gravity.

A. Streak

Identify the FALSE statement. Silicates: A. are a large category of minerals and include the common minerals calcite and dolomite. B. have the silicon-oxygen tetrahedron as their structural unit. C. are classified on the basis of how the tetrahedrons join and share oxygen atoms. D. are a major component of continental crust.

A. are a large category of minerals and include the common minerals calcite and dolomite.

Which of the following statements is FALSE? Crystals: A. are formed by the high-temperature, extremely rapid process known as solid-state diffusion. B. display symmetry. C. grow outward from a seed. D. have an orderly internal arrangement of atoms arranged in a lattice pattern.

A. are formed by the high-temperature, extremely rapid process known as solid-state diffusion.

Which of the following statements is FALSE? Formation of table salt: A. is an example of solidification of a melt. B. is, in mineralogic terms, formation of the halide mineral halite. C. results in cubic crystals. D. takes place when a solution has become saturated.

A. is an example of solidification of a melt.

Which of the following is NOT a mineral? A. oil, because it's a liquid, not a solid B. a gold nugget, because it's a native metal C. pyrite, because it's a chemical compound D. an oyster shell, because it's not crystalline

A. oil, because it's a liquid, not a solid

Which of the following is a mineral? A. salt (NaCl) B. amber (tree sap) C. glass D. sugar (formula C6H12O6)

A. salt (NaCl)

Graphite is: A. the "lead" in the pencil you write with. B. the polymorph of galena. C. harder than glass. D. pure silicon.

A. the "lead" in the pencil you write with.

Which of the following statements accurately describes a property that is NOT useful in identifying quartz? A. Fracture, because quartz does not have fracture. B. Color, because quartz can be many different colors. C. Crystal habit, because quartz has a fibrous crystal habit. D. Hardness, because quartz is softer than most minerals on Mohs scale.

B. Color, because quartz can be many different colors.

Which is NOT a physical property commonly used in the lab or field to identify minerals? A. specific gravity B. X-ray diffraction C. luster D. color

B. X-ray diffraction

Calcite and aragonite minerals that constitute clam shells are examples of which method of mineral formation? A. solid-state diffusion B. biomineralization C. solidification of a melt D. precipitation from a solution

B. biomineralization

An unknown mineral scratches glass, has only average specific gravity, and shows no cleavage but does show conchoidal fracture. Which of the following could it be? A. mica B. halite C. quartz D. talc

C. quartz

Which of the following groups of silicate minerals exhibits a single strong cleavage in one direction? A.framework silicates B. single-chain silicates C. sheet silicates D. independent tetrahedra silicates

C. sheet silicates

The tendency of a mineral to break and produce smooth, curving, shell-shaped surfaces is termed: A. streak. B. cleavage. C. luster. D. conchoidal fracture.

D. conchoidal fracture.

There are two physical properties of minerals that both result in smooth, flat surfaces with specific angles between them. The first property is externally visible and is the result of how the mineral forms; the second is inherently internal and is the result of breaking a sample of the mineral. These properties are called: A. cleavage and crystal habit. B. hardness and cleavage. C. cleavage and hardness. D. crystal habit and cleavage.

D. crystal habit and cleavage.

Which chemical bond results from the transfer of electron(s) from one atom to another so that the donor atom attains a negative charge (anion) and the receiving atom gains a positive charge (cation)? A. van der Waals B. covalent bond C. hydrogen bond D. ionic bond

D. ionic bond