Download Minerals, Rocks and Resources

Minerals & Rocks
Minerals
• A naturally formed, inorganic solid with
crystal structure and definate chemical
composition.
– The substance was not formed by or from living
things such as plants or animals
• Made from Chemical elements or compounds
• Minerals can be identified
by their physical and
chemical properties
– Luster, Streak, Crystal,
Hardness, Density
and Structure.
Luster
• The way a
mineral reflects
light
– Metallic Luster
• hard, shiny
– Nonmetallic
Luster
• shiny, glassy,
waxy, pearly,
earthy (dull)
Streak
• The streak is the color of the mineral in
powdered form.
• The streak is found by rubbing a fresh corner
of the mineral across a white, unglazed streak
plate
• Some metallic minerals
leave behind a powder
that is not the same
color as the mineral.
• The color of the mineral is not always the
same as the streak! Streak is more reliable.
Crystal Structure
• A regularly shaped solid formed by an
repeating ordered pattern of atoms
– Examples include: Six sided, cubic,
rectangular, sheets, fibers
Hardness
• A measure of how easily a mineral can be
scratched.
• Minerals can be tested by scratching the
unknown mineral with the edge or point of
other materials of known harness
Mohs Scale of Hardness
Density
• Can be found by either dividing the mass of a
sample by its volume or flotation
• Water’s density is 1 g/mL
• A substance will sink in water if it is more
dense than 1g/mL and float if it is less dense
than 1g/ML
Rocks
• Nearly all rocks are
composed of one or
more minerals
• Geologists classify rocks
according to how they were formed
– Igneous rocks form from lava when it reaches
the surface, cools and solidifies
– Sedimentary rocks result from the compaction
and cementing of layers of sediment
– Metamorphic rocks form when other types of
rocks are changed by heat and/or pressure
Igneous Rocks
• The result of the solidification
of magma or lava
• Most lack layering, however
successive lava flows can
form a layered rock structure
• Those that cool slowly, deep
within Earth, are composed
of large crystals
• Those that cool faster, at or
near the Earth’s surface,
have smaller or no visible
crystals
Igneous Rock Formation
Igneous Rock Classification
Sedimentary Rocks
• Most are composed of the weathered
remains of other rocks
• Usually are formed by the compression and
cementing of particles
of sediment
• Generally exist as
a thin layer over
metamorphic and
igneous rocks
Sedimentary Rock Characteristics
• Fragmental rocks are made up of different sized
particles such as shale, sandstone and
conglomerate (composed of pebbles or larger
stones held together by natural cement)
• Organic sedimentary rock contain the accumulation
of plant and animal remains
– Fossils are commonly found
• Chemical sedimentary rocks are deposited by the
settling of materials from solution in seawater
– This occurs during the evaporation of seawater and when
chemical reactions in the water form compounds that
settle
– Rock Salt is an example
Sedimentary
Rock
Classification
Metamorphic Rocks
• Form when sedimentary and
igneous rocks are changed by
heat and/or pressure
• The only kind of rock that forms directly from
another rock
• Metamorphism may cause structures, such as
layering, to become distorted or to disappear
• It also may cause new minerals to form, and/or
crystals to grow
• Most are formed deep within the Earth and
pushed to the surface when mountains are
formed
Metamorphic Rock Classification
• Texture
– Appearance and feel of the rock surface
• Grain Size
• Composition
• Type of Metamorphism
Metamorphic Rock Classification
The Rock Cycle
• Natural changes in rocks and rock material that
takes place at the Earth’s surface and within Earth
• Nearly all rocks are
made from the remains
of other rocks
• Rocks are classified
based of their origin
• Rocks can change in
response to changing
conditions at the surface
or within Earth
The Rock Cycle