2-1 Notes Properties of Minerals (front side)
liquid- a substance that flows, whose shape can change, and has a definite volume
solid- a substance that resists changing shape and has a definite volume
gas- a substance that has no definite shape and no definite volume
A mineral must have ALL of the following characteristics:
1.
2.
3.
4.
5.
naturally occurring (not man made)
solid
inorganic (not formed from living things or remains of living things)
crystal structure (atoms arranged in a pattern with flat sides, faces, and edges)
definite chemical composition (contains elements in definite proportions)
ex
H2O-water must have 2 hydrogen and 1 oxygen atoms
element- substance composed of a single kind of atom
ex
C (carbon) ex O2 Oxygen
compound- 2 or more elements combined so that the elements no longer have distinct
properties
ex
H2O is a liquid made from 2 gases
Geode-hollow rock where mineral crystals have grown inside
vein- narrow deposit of a mineral that is different from the surrounding rock
ore- deposit of minerals contained in rocks
rock- made up of a mixture of mineral and other materials
2-1 Notes Properties of Minerals (back side)
Identifying minerals by physical properties:
1. color-not very reliable
2. luster- how light is reflected from its surface
3. streak- the color of its powder
4. hardness (most useful property)
-Mohs hardness scale-rank minerals from 1 to 10 determined by a scratch
test (a mineral can scratch any mineral softer than it and can be scratched
by any mineral harder than it)
5. density-mass in a given space (heaviness) D=mass/volume
6. crystal structure
7. how it breaks: cleavage- ability to split easily along flat surfaces
fracture-breaks apart in an irregular way
8. special properties such as magnetic, glows under an ultraviolet light, tastes salty,
reacts with acid, or radioactive
Minerals can form in 3 ways:
1. from organic processes
ex
shells
2. dissolved in solutions (mixture in which one substance is dissolved in another)
ex
water and calcium after the water evaporated
3. When magma (molten, hot liquid, under the Earth’s crust) or
lava (magma that reaches Earth’s surface) cools
The majority of Earth’s crust is formed from silicates (rich in silicon and oxygen).
Slow cooling magma and lava create large crystals.
Rapidly cooling magma and lava create small or no crystals.
2-2 Notes Classifying Rocks (front side)
To study a rock sample, geologists observe the rocks
1. mineral composition (what it is made of)
2. color
3. texture- look and feel of the rock’s surface
Particles of minerals called grains gives the rock its texture
1. coarse-large and easy to see
2. fine-small and must need a microscope to see
3. banded-lie in patterns of flat layers or swirls
Rocks are classified into 3 major groups by their origin (the way they were formed):
1. igneous rock- forms form the cooling of magma or lava
2. sedimentary rock-forms when small particles of rock or the remains of animals or
plants are pressed together (compacted) or cemented together, usually in
layers
3. metamorphic rock- forms when a rock is changed by heat, pressure, or chemical
reactions, mostly underground
-can be igneous, sedimentary, or other metamorphic rock
-classified by arrangement of the grains of the rock
igneous rocks- 1. extrusive igneous rock forms from lava that has erupted onto Earth’s surface
ex
basalt, obsidian, pumice
-cools rapidly forming fine grained rock with small or no
crystals
2. intrusive igneous rock forms from magma that hardened beneath the surface
of earth
ex
granite
-cools slowly forming coarse grained rock with large
crystals
2-2 Notes Classifying Rocks (back side)
sedimentary rocks- 1. clastic rock- forms when rock fragments are squeezed together
ex
shale, sandstone, conglomerate
2. organic rock – forms from material once part of living things or made
by living things
ex
coal, limestone
3. chemical rocks- forms when minerals dissolved in a water solution
crystallize or the water evaporates ex halite
metamorphic rocks- 1. foliated rock- forms when grains arranged in either parallel layers or
bands
ex
granite becomes gneiss
ex
shale becomes slate
2. nonfoliated rock forms when grain is arranged randomly
ex
quartz becomes quartzite
ex
limestone becomes marble
2-6 Notes The Rock Cycle
The Rock Cycle- series of processes that occur on Earth’s surface and in the crust and mantle
that slowly change rocks from one kind to another kind:
igneous rock by melting rock and then solidification of the rock
sedimentary rock by weathering and/or erosion then deposition (laid down) of
sediments then burial and cementing
metamorphic rock by heat and/or pressure then metamorphism (change)
plate movement creating magma for igneous rocks:
1. oceanic plates move apart then magma formed from melted mantle rock moves
upward to fills the gap then cools and hardens (solidifies)
2. oceanic plate subducts (sinks beneath in a deep ocean crack back into the mantle)
then melts to form magma that rises and solidifies making volcanos
3. collision of continental plates pushes rocks deep into the
Earth so the rocks melt to form magma
plate movement creating sedimentary rocks: collision of continental plates can push up
mountain ranges then wear away rock due to weathering, erosion, and deposition
(process in which sediment is laid down in a new location) leading to burial and
cementing which creates sedimentary rock
plate movement creating metamorphic rocks: collision between continental plates can push
rock deep beneath the surface of the Earth where heat or pressure could cause the rock
to change (metamorphism)