Download EH_ Inv2_Minerals - Prospect Ridge Academy

Warm Up
• Draw a picture of what you think the inside
of the earth looks like.
• Put a star where you think you would find
minerals.
• Write whether you agree or disagree with
the following statements.
– A mineral is anything solid on Earth.
– The best way to identify a mineral is by color.
– Hardness, streak, and luster are among the
properties used to identify minerals
Objectives
• SWBAT define mineral.
• SWBAT explain how a mineral forms.
• SWBAT list how mineral are categorized.
What are minerals
and why are they
useful?
What is a mineral?
• What is a mineral?
• What are the common rock-forming
minerals?
• How do minerals form?
What is a mineral?
• Mineral
• crystallization
• Magma
• cleavage
• fracture
• density
• luster
• streak
• hardness
What is a mineral?
• A mineral is a naturally occurring,
inorganic solid with a definite chemical
composition and an orderly
arrangement of atoms or ions.
• There are approximately 4,000
minerals on Earth, but only about 30
are common.
What is a mineral? (cont.)
What is a mineral?
What is a mineral? (cont.)
• Minerals have a definite chemical
composition.
– Always contains certain elements in the
same proportion.
• Some minerals, such as silver and
sulfur, are composed of just one
element.
• But, most minerals are compounds, (two or
more different elements chemically joined).
What is a mineral? (cont.)
• Minerals form predictable crystal
patterns.
– particles line up in a regular, repeating
pattern.
– flat sides called faces, that meet at
sharp edges and corners.
What is a mineral? (cont.)
A crystal is a solid with a repeating
arrangement of atoms or ions in 3
directions.
What is a mineral? (cont.)
• Minerals are solids, meaning they have
an orderly internal arrangement of
atoms or ions.
• Minerals are inorganic, or they are
naturally occurring made from nonliving things
• Despite being inorganic, some
minerals can form as a result of
organic processes.
The Structure of Minerals
• Minerals occur in many different
shapes.
• When a crystal forms under the right
conditions and has time to grow, it will
develop a characteristic crystal shape.
• Most of the time, minerals grow in tiny
clusters.
The Structure of Minerals (cont.)
• The common rock-forming minerals are
composed of combinations of elements
that are abundant in Earth’s crust.
• Oxygen and silicon are the two most
plentiful elements in the crust.
How do minerals form?
• All minerals form through crystallization.
• The process of crystallization occurs
when particles dissolved in a liquid or a
melt solidify and form crystals.
• The chemical and physical properties of
minerals can help geologists infer the type
of environment where these minerals
formed.
How do minerals form? (cont.)
• Minerals can also form from magma.
Magma is molten material stored
beneath Earth’s surface.
• When magma erupts on or near Earth’s
surface, it is called lava or ash.
lava
from Latin lavare, means “to wash”
How do minerals form? (cont.)
• As lava or ash cools above ground or
magma cools underground, atoms and
ions arrange themselves and form
mineral crystals.
• Small crystals form as lava cools
quickly on or near Earth’s surface and
large crystals sometimes form as
magma cools and crystallizes slowly
below Earth’s surface.
How do minerals form? (cont.)
• Minerals that form deep within Earth’s
crust and mantle are stable under high
pressure and high temperature
conditions.
• Metamorphic activity can uplift minerals
from great depths onto Earth’s surface.
• Changes in pressure and temperature on
Earth’s surface combined with agents of
erosion can cause minerals to break
down and eventually form new minerals.
• Put a star next to the information that is
most important on your notes sheet.
• Use the objectives.
Physical Properties
• Color alone cannot be used for mineral
identification because many different
minerals can be the same color.
Physical Properties (cont.)
• Luster
– The way a mineral
reflects light.
– Can be metallic or
non-metallic.
– Shiny or dull.
– waxy, pearly, glassy.
This is a gem
stone called
tourmaline it has a
glassy luster
• Streak
– The color of its powder.
– Not always the same as
the color of the mineral.
• Streak is only useful for
identifying minerals that
are softer than
porcelain.
• Nonmetallic minerals
generally produce a
white streak.
http://geology.csupomona.edu/alert/mineral/streak.htm
Physical Properties (cont.)
• Hardness
– A measure of how
easily a mineral can
be scratched.
http://www.info-diamond.co.uk
Physical Properties (cont.)
• Friedrich Mohs developed the Mohs’
hardness scale to compare the
hardness of different minerals, with
scale ranging from 1 to 10.
Physical Properties (cont.)
• Sometimes the way a mineral breaks
provides clues to its identity.
• The arrangement of atoms or ions and
the strengths of their chemical bonds
determine how a mineral breaks.
• Minerals break where bonds between
atoms or ions are weak.
Properties of Minerals
• Density
– Minerals will have a
certain density
regardless of the size
of the sample.
http://www.astronomynotes.com/cosmolgy/
Physical Properties (cont.)
• If a mineral breaks with smooth, flat
surfaces, it has cleavage.
• If a mineral breaks and forms uneven
surfaces, it has fracture.
cleavage
from Old English cleofan, means
“to split, separate”
• Color
– first thing noticed
about minerals
• Some minerals have
special properties,
such as texture, odor,
fluorescence,
magnetism, or the
way they react when
they come in contact
with hydrochloric acid.
http://www.nmnh.si.edu/rtp/students/2004/virtualposters/poster
Wrap Up
• Identify all the properties used to
classify an unknown mineral.
• How are minerals formed?