Transcript chapter-2-lesson-1-rocks-and

Rocks and Minerals
Chapter 2 Lesson 1
Introduction
The famous naturalist John Muir first climbed to the summit of Cathedral Peak in
1869. Located in the Sierra Nevada Range in California, it is 3,308 meters in
elevation. Cathedral Peak is mostly composed of granite, a mixture of quartz,
feldspar, and other minerals such as hornblende, and mica. Looking down from
this tall, narrow peak, you would probably feel like you were on top of the world!
Quartz
hornblende
mica
Cathedral Peak
in California
Elevation of 10,916 feet (3,327 meters)
Vocabulary
▪ Mineral-is a naturally occurring solid that can form by inorganic processes
and that has a crystal structure and a definite chemical composition
▪ Inorganic-formed from materials that were not a part of living things
▪ Crystal-the repeating pattern of a mineral’s particles that forms a solid
▪ Streak-the color of a mineral’s powder
▪ Luster-term used to describe how light is reflected from a mineral’s surface
▪ Cleavage-how the mineral can split apart
▪ Fracture-how the mineral looks when it breaks
Vocabulary
▪ Mohs hardness scale-used to rank the hardness of minerals; it is ranked from
1-10
▪ Geode-a rounded, hollow rock that is often lined with mineral crystals.
Geologists believe crystals are formed inside geodes.
▪ Crystallization-the process by which atoms are arranged to form a material
that has a crystal structure
▪ Solution-a mixture in which one substance is dissolved in another
▪ Vein-a narrow channel or slab of a mineral that is different from the
surrounding rock
What Is a Mineral?
▪ Look at these two substances. On the left is a hard chunk of coal.
On the right are beautiful quartz crystals. Both are solid materials
that form beneath Earth’s surface. But which is a mineral?
Defining Minerals
A mineral is a naturally
occurring solid that can
form by inorganic
processes and has a
crystal structure and a
definite chemical
composition. For a
substance to be a
mineral it must have all
five characteristics. So,
is either quartz or coal a
mineral?
Properties of Minerals
▪ Naturally Occurring
▪ Solid
All minerals are substances that
are formed by natural
processes. Quartz forms
naturally as molten material
called magma cools and
hardens beneath Earth’s
surface. Coal forms naturally
from the remains of plants that
are squeezed tightly together.
A mineral is always a solid, with
a definite volume and shape.
The particles that make up a
solid are packed together very
tightly, so they cannot move
like particles that make up a
liquid. Coal and quartz are
solids.
Properties of Minerals
▪ Crystal Structure
▪ Form by Inorganic Processes
The particles of a mineral line up in
a pattern that repeats over and
over again. The repeating pattern
of a mineral’s particles forms
crystals. A crystal has flat sides,
called faces, that meet at sharp
edges and corners. The quartz has
a crystal structure. In contrast,
most coal lacks a crystal structure.
All minerals must be able to form
by inorganic processes. Quartz can
form naturally as magma cools.
Coal comes only from living thingsthe remains of plants that lived
millions of years ago. But some
minerals that can form from
inorganic processes may also be
produced by living things.
Properties of Minerals
▪ Definite Chemical Composition
A mineral has a definite chemical composition. This
means that a mineral always contains certain elements
in definite proportions. An element is a substance
composed of a single kind of atom. Quartz always
contains one atom of silicon for every two atoms of
oxygen. The elements in coal vary over a wide range.
Classify
Complete the
checklist. Are
quartz and coal
minerals or only
naturally occurring
substances?
Mineral Characteristics
Naturally occurring
Can form by inorganic
processes
Solid
Crystal structure
Definite chemical
composition
Quartz
Coal
Apply
Classify wood by
writing a check mark
to the characteristic it
has. Then answer the
question: Is it a
mineral? Explain your
answer.
Mineral Characteristics
Naturally occurring
Can form by inorganic process
Solid
Crystal Structure
Definite chemical
composition
Wood
Difference between Rocks and Minerals
https://youtu.be/ZkHp_nnU9DY
Let’s Watch
https://youtu.be/32NG9aeZ7_c
https://youtu.be/rQsKRWiy-uE
Let’s Apply!
Rocks
Minerals
In your Science
notebook, create a
Venn diagram like
this one to
compare rocks and
minerals.