Ch. 3 - Minerals and Rocks
Which of the following is NOT true about minerals?
All minerals are compounds of more than one element.
What is the definition of a rock?
Discussion Points: A rock is.... COHERENT NATURALLY occurring SOLID consisting of an AGGREGATE of MINERAL GRAINS (or made of GLASS)
How are sedimentary rocks different from igneous rocks?
Discussion Points: Igneous - Solidification of a melt (above or under the ground) Sedimentary - cementing of grains OR precipitation of mineral from water (at or near earth's surface)
What is a thin section and how are they used in geologic study?
Discussion Points: Very thin slice glued to a glass slide Petrographic microscope Ability to see grains @ high magnification Polarized light=different colored minerals
Carbon-containing compounds that either occur in living organisms or resemble compounds in living organisms are called...
Organic Compounds
The internal ordering of mineral crystals can be detected using...
X-ray Diffraction
Trace amounts of impurity in a mineral can commonly produce significant differences in __________ among individual crystals of the mineral.
a. Color
In a mineral specimen of quartz, what is the term for the smoothly curving, clamshell-shaped surface? (on the test, this one will have a picture)
a. Conchoidal fracture
What type of rock forms by the solidification of a melt?
a. Igneous
For most minerals, the streak color obtained when the mineral is scratched against a porcelain plate is...
a. Only useful if the mineral is softer than porcelain.
A facet is a __________ on a gem.
a. Polished surface
Potassium feldspar (KAlSi3O8) is in which mineral class?
a. Silicates
The mantle is composed almost entirely of the mineral class:
a. Silicates
The mineral class that makes up more than 95% of rocks in the continental crust is termed the....
a. Silicates.
Which class of minerals is highly conductive because of metallic bonding?
a. native metals (not totally sure about this one, but the other 3 are all made out of non-metals so I'm educated guessing)
Cleavage in minerals refers to...
b. A tendency to break along planes of weakness.
The silicates are broken into several groups based on the way silica tetrahedra are...
b. Arranged and bonded.
Which of the following is NOT a way for minerals to crystallize?
b. Bonding carbon to oxygen atoms to form organic compounds
What mineral reacts with hydrochloric acid? (on the test, this one will have a picture)
b. Calcite
Minerals are grouped into mineral classes primarily on a basis of...
b. Chemistry, specifically the anions within the chemical formula.
Using Mohs hardness scale, which of the following statements is FALSE? (on the test, this one will have a picture)
b. Diamonds are twice as hard as apatite.
In which type of silicate are the greatest proportion of oxygen atoms shared by pairs of adjacent tetrahedra?
b. Framework silicates
Which of the following minerals is more commonly known as table salt?
b. Halite
Ore minerals, such as galena, tend to be different from typical minerals (such as quartz) in that they have a...
b. Large specific gravity
Geologists refer to an exposure of bedrock on the surface as a(n)...
b. Outcrop
Which layer of Earth does NOT contain silicate minerals?
b. Outer core
Which of the following common minerals is softest?
b. Talc
The __________ class of minerals includes a substance commonly known as table salt.
b. halides
What type of rock forms when preexisting rocks undergo changes in response to a modification of their environment, without first melting?
b. metamorphic rocks
Which of the following is NOT a mineral?
b. petroleum
The mineral olivine is in the __________ mineral class.
b. silicate
The __________ class of minerals contains the anion S^c.
b. sulfides
With regard to minerals, hardness refers to the ability to resist...
c. Being scratched.
Calcite (CaCO3) is in which mineral class?
c. Carbonates
Synthetically made glass and natural quartz crystals both exhibit a fracture pattern termed...
c. Conchoidal fracture.
Which of the following is NOT a way in which specific rock types can be distinguished from one another?
c. Crystal shape
The diamonds typically seen in engagement rings today do not display their natural crystal faces but rather __________, which are made by grinding the gem on a spinning lap.
c. Facets
A __________ is a mineral-lined cavity in a rock.
c. Geode
Which of the following is a mineral?
c. Ice (water in the solid state)
Diamonds are usually found in...
c. Kimberlite
Which of the following minerals is a silicate?
c. Olivine
Which common rock-forming mineral shows up in all three major rock types (igneous, sedimentary, and metamorphic)?
c. Quartz
Which of the following forms either by the cementing together of grains broken off preexisting rocks or by the precipitation of mineral crystals out of water solutions at or near the Earth's surface?
c. Sedimentary rocks
A mineral property defined by the density of the mineral sample divided by the density of water (1.0 g/cm3) is...
c. Specific gravity.
The tetrahedral structure that forms the backbone of all silicate minerals is composed of silicon and what other element?
c. oxygen
Which of the following is a mineral?
d. Calcite
Minerals that grow around volcanic vents MOST likely form by...
d. Precipitation from a gas
The color of a mineral in powdered form is termed...
d. Streak
Pyrite (FeS2) is in which mineral class?
d. Sulfides
Minerals are all naturally occurring solid substances with a definable chemical composition. They must also possess...
d. a fixed crystalline structure (spatial arrangement of atoms and ions)
The framework silicates are the MOST complicated because...
d. all tetrahedral oxygens are shared
Natural glass is NOT considered a mineral because it...
does not have a fixed crystalline structure.
When a solution becomes oversaturated, new solid particles are said to...
Precipitate from the solution
