Study Guide – Chapter 2
Test—Minerals and Rocks
KNOW
ALL OF YOUR VOCABULARY!!! TAKE HOME YOUR
VOCABULARY FOLDER!!!
THERE
WILL BE A MATCHING OR SHORT ANSWER QUESTION FOR THESE WORDS!!!
Minerals—natural
occurring solids that can form by inorganic (not living) processes and that
have a crystal structure and a definite chemical composition!
For
a substance to be a mineral, it must have all five of these characteristics:
1-naturally
occurring
2-solid
3-crystal
structure
4-forms
by inorganic processes
5-definite
chemical composition
QUARTZ
is a mineral!
How are minerals
identified?
Answer: Each mineral has characteristic properties
that can be used to identify it. These
properties are:
1-color
2-streak-the color of its powder
3-luster-how light is reflected
from a mineral’s surface
Types
of luster are:
-metallic
-silky
-waxy,
greasy, earthy, or pearly
-glassy
4-hardness
THE
HARDEST MINERAL IS A DIAMOND!
5-density—mass in a given space
6-crystal structure
8-cleavage and fracture
9-special properties—Examples: Calcite bends light to produce double
images! Some minerals conduct
electricity, glow when placed under ultraviolet light, or are magnetic.
How do minerals form?
1-organic
materials
2-minerals
from solutions
3-minerals
from magma and lava
How
do geologists classify rocks?
Answer: To study a rock sample, geologists observe
the rock’s mineral composition, color, and texture.
What
are the three major groups of rocks?
1-igneous—forms
from the cooling of magma or lava—Magma
hardens underground to form rock. The
lava erupts, cools, and hardens to form rock on the Earth’s surface.
2-sedimentary--forms
when small particles of rocks or the remains of plants and animals are pressed
and cemented together—Forms in layers
that are buried below the surface.
3-metamorphic—forms
when a rock is changed by heat or pressure, or by chemical reaction. Most
metamorphic rocks form deep underground!
How
do geologists classify igneous rocks?
Answer: Igneous rocks are classified by their:
1-origin—Igneous rocks may form on (extrusive igneous rock) or beneath (intrusive igneous rock)
the Earth’s surface!
BASALT
IS THE MOST COMMON EXTRUSIVE ROCK!
GRANITE
IS THE MOST ABUNDANT TYPE OF INTRUSIVE ROCK IN CONTINENTAL CRUST!
2-texture—the texture depends on
the size and shape of its mineral crystals (except the different types of
volcanic glass—igneous rocks that lack a crystal structure).
3-mineral composition—The silica
content of magma and lava can vary. Lava
that is low in silica usually forms dark-colored rocks such as basalt! Magma that is high in silica usually forms
light-colored rocks such as granite!
How
are igneous rocks used?
Answer: Igneous rocks are used as tools and building
materials.
How
do sedimentary rocks form?
Answer: Most sedimentary rocks are formed through a
sequence of processed:
1-weathering
2-erosion
3-deposition
4-compaction
5-cementation
What
are the three major types of sedimentary rocks?
1-clastic
rocks-formed when rock fragments are squeezed together
2-organic
rocks-formed where the remains of plants and animals are deposited in layers
3-chemical
rocks-formed when minerals dissolved in a water solution crystallize
How
are sedimentary rocks used?
Answer: Sedimentary rocks have been used throughout history
for tools and building.
What
are metamorphic rocks?
Answer: Any rock that forms from another rock as a
result of changes in heat or pressure (or both heat and pressure) is a
metamorphic rock.
How
are metamorphic rocks classified?
Answer: Geologists classify metamorphic rocks
according to the arrangement of the grains making up the rocks.
Foliated rocks—describes the thin, flat
layering found in most metamorphic rocks.
Examples of foliated
rocks: gneiss and slate
Nonfoliated rocks—the mineral grains in
these rocks are arranged randomly.
Examples of nonfoliated
rocks: marble and quartzite
How
are metamorphic rocks used?
Answer: The metamorphic rocks marble and slate are
important materials for building and sculpture.
What
is the rock cycle?
Answer: The rock cycle is a series of processes that
occur on Earth’s surface and in the crust and mantle that slowly change rocks
from one kind to another.
Example: Weathering can break down granite into
sediment that later forms sandstone!
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