CH 3
What is the prime characteristics that geologists use to separate minerals into classes?
chemical composition (specifically, the anions in the chemical formula)
The tendency of a mineral to break and produce smooth, curving, shell-shaped surfaces is termed:
conchoidal fracture.
Which type of chemical bond occurs when atoms share electrons
covalent
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:
crystal habit and cleavage.
Calcite and aragonite minerals that constitute clam shells are examples of which method of mineral formation?
biomineralization
Which of the following statements is FALSE? Formation of table salt: Choose one: A. results in cubic crystals. B. is an example of solidification of a melt. C. is, in mineralogic terms, formation of the halide mineral halite. D. takes place when a solution has become saturated.
is an example of solidification of a melt
Why is glass not a mineral?
it does not have a fixed crystalline structure
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?
quartz
Which of the following groups of silicate minerals exhibits a single strong cleavage in one direction?
sheet silicates
When you scrape a mineral along a ceramic plate to observe the color of its powder, you are checking the physical property known as:
streak
Graphite is:
the "lead" in the pencil you write with.
Which of the following statements is FALSE? Crystals: A. have an orderly internal arrangement of atoms arranged in a lattice pattern. B. are formed by the high-temperature, extremely rapid process known as solid-state diffusion. C. display symmetry. D. grow outward from a seed.
B. are formed by the high-temperature, extremely rapid process known as solid-state diffusion.
T OR F ABOUT DIAMONDS:are found in carrot-shaped structures called pegmatites.
F
T OR F ABOUT GEMSTONES:In order to be considered precious or semiprecious, a gemstone must be transparent.
F
T OR F ABOUT SILICATES: are a large category of minerals and include the common minerals calcite and dolomite.
F
T OR F about quartz: Quartz can be many different colors.
F
T OR F: Polymorphs of the same mineral have the same crystal shape because they contain the same basic atoms bonded in the same way.
F
Which of the following is NOT a mineral? Choose one: A. oil, because it's a liquid, not a solid B. a gold nugget, because it's a native metal C. an oyster shell, because it's not crystalline D. pyrite, because it's a chemical compound
Oil
Which of the following is a mineral? Choose one: A. salt (NaCl) B. glass C. amber (tree sap) D. sugar (formula C6H12O6)
Salt (NaCl)
T OR F ABOUT DIAMONDS:are brought from the mantle to the surface in magma that hardens into kimberlite.
T
T OR F ABOUT DIAMONDS:of industrial quality are used as abrasives.
T
T OR F ABOUT DIAMONDS:that have weathered out of ore bodies can end up in stream gravels.
T
T OR F ABOUT GEMSTONES:Many gemstones come from pegmatites, which are particularly coarse-grained igneous rocks.
T
T OR F ABOUT GEMSTONES:Ruby is a gemstone variety of the common mineral corundum.
T
T OR F ABOUT QUARTZ: Quartz has a fibrous crystal habit.
T
T OR F ABOUT QUARTZ:Quartz is softer than most minerals on Mohs scale.
T
T OR F ABOUT SILICATES: have the silicon-oxygen tetrahedron as their structural unit.
T
T OR F ABOUT SILICATES:are a major component of continental crust
T
T OR F about quartz:Quartz does not have fracture.
T
T OR F: Crystals can be a variety of geometric shapes, including cubes, trapezoids, pyramids, octahedrons, hexagons, columns, blades, and needles.
T
T OR F: 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.
T
T OR F:There is an angle of 120° between each crystal face of the hexagonal column of a quartz crystal.
T
T OR FALSE ABOUT GEMSTONES:A gemstone is a mineral that has value because of its rarity and beauty.
T
T OR FALSE ABOUT SILICATES: are classified on the basis of how the tetrahedrons join and share oxygen atoms.
T