(Basic Learning and Essentials in Science for Secondary Education)
EARTH & LIFE SCIENCE
UNIT 2
(Minerals and Rocks)
He is the Rock, his works are perfect, and all his ways are just. A faithful God who does no wrong,
upright and just is he.
-Deuteronomy 32:4
Earth Science
1
Eldon Karl M. Dumelod, LPT
Project BLESSED (Basic Learning and Essentials in Science for Secondary Education)
BSEd- SCIENCE MAJOR
Earth Science 101
Unit 2- Module 4:
Minerals
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Development Team of the Module
Writer:
Eldon Karl M. Dumelod
Editors :
Raymus A. Sta. Cruz, Janwin C. Magas, Samuel A. Reyes
Layout Artist:
Eldon Karl M. Dumelod
Management Team
Chairpersons:
GRACE M. CASAUAY, Ph.D.
DEAN, TELA
FRANKLIN L. SORIANO, Ph.D.
Vice President for Academic Affairs
Earth Science
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Eldon Karl M. Dumelod, LPT
INTRODUCTORY MESSAGE
For our beloved Science Major:
Welcome to Earth Science a Project BLESSED (Basic Learning and Essentials in Science for Secondary Education) Module
on Minerals and Rocks!
This module will serve as tool in providing wisdom and guidance to understand our planet earth. It is designed in such way
that it meets the present demand of upgrading the standard of Senior High School education in our country. This module was also
designed to provide you with fun and meaningful opportunities for guided and independent learning at your own pace and time.
This module has the following parts and corresponding icons:
Serves as a bird’s eye view of what will be discuss in the entire module.
Provides a step by step process on how you should study the module.
Gives you details when you will submit or need to finish the module together with the
consultation hour.
This will give you an idea of the skills or competencies you are expected to learn in the
module.
It serves as a framework of the whole topic that will be discuss in this module.
Serves as a diagnostic test to assess prior knowledge.
Gives a detailed discussion about the given topics.
Can be found every after lesson to see how well you understood the topic.
Serves as a simplifying activity to sum up the discussion.
Assess you on how far you have mastered the competencies
Serves to measure your achievement and the effectiveness of the module.
An alphabetical list of important terms or acronyms that are use in this module
This is a list of all sources used in developing this module.
With these several features provided, I hoped that this module will contribute to the enhancement of your learning and
understanding our very own planet.
A special word for every students from the book of Proverbs 4:5-9 “Get wisdom! Get understanding! Do not forget, nor turn
away from them...Wisdom is the principal thing; therefore, get wisdom. And in all your getting, get understanding. Exalt her, and she will
promote you; She will bring you honor, when you embrace her…a crown of glory she will deliver to you.”
Earth Science
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Eldon Karl M. Dumelod, LPT
TABLE OF CONTENTS
Cover
1
Introductory Message
3
Table of Content
4
Module Title
5
What Is This Module about?
6
How Do You Use This Module?
6
Time Frame
6
UNIT 2: MINERALS AND ROCKS

MODULE 4: Minerals
7
Learning Objectives
7
Concept Map
7
Pre- Assessment
7
Lesson 4: Minerals
10
Post- Assessment
23
Feedback
25
References
25
Earth Science
4
Eldon Karl M. Dumelod, LPT
BACHELOR OF SECONDARY EDUCATION
SCIENCE MAJOR
EARTH SCIENCE
MODULE 4
(Minerals)
In this module, you will learn about:
1.1.
different characteristics of a mineral
1.2. identify common rock-forming minerals using their physical
and chemical properties.
Earth Science
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Eldon Karl M. Dumelod, LPT
This module introduces you to Earth Science, the multi disciplinary study of the past, present and future of
planet earth and the universe. This module includes topics about minerals and rocks. It covers two (2) topics that a
Grade 11/ 12 student ought to understand, these are:
1.
Characteristics of Minerals
2.
Physical and Chemical Properties of Minerals
I know that you are already excited to get started, however, there are some tips that you have to remember
so that you will get the most from this module all you need to do are the following:
1.
Begin by reading and understanding the learning outcomes.
2.
Take the pre-test before proceeding to the discussion proper. The test can give you an idea of
how much time you will allot in each lesson. Be sure to answer your pre-test first before you
check your answer with the help of answer key. I will give the answer key of your pre-test at the
back part of your module. Honesty is highly appreciated.
3.
Follow the directions and/or instructions in the activities diligently.
4.
Answer all the given checkpoints and activities except for the key questions. It will serve as your
guide questions on each topic/ lesson.
5.
Read carefully the discussion section. It contains important notes or basic information that you
need to know.
6.
You must be able to apply in real- life situation what you learned in the experiment activity.
7.
Perform the hands- on activity. It will help you understand better the topic being discussed.
8.
Answer the post-test so that you will know how much you have learned from the lessons.
9.
Each lesson also provides you with references and definitions of key terms for your guide. They
can be of great help. Use them fully.
This module should be completed within a week.
If you set an average of 1 hour per day, you should be able to complete the module comfortably by the end
of the assigned week.
Try to do all the learning activity. If you do not get a particular question right in the first attempt, you
should not get discouraged but instead, go back and do it again. If you still do not get it right after several attempts
then you should seek help from your teacher or adviser.
Suggested Allotment Time
Released Date
Consultation Hour
Retrieval Date
: 2 weeks
:
:
:
DO NOT LEAVE ANY QUESTION UNANSWERED EXCEPT FOR KEY QUESTIONS
Earth Science
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Eldon Karl M. Dumelod, LPT
Minerals
At the end of this lesson, you will be able to:
a. Discuss the different characteristics of a mineral
b. Identify common rock-forming minerals using their physical and chemical
properties.
Characteristic
Crystal Form and Habits
Composition
Cleavage and Fracture
Crystal Structure
Luster
Physical Properties
Color and Streak
Minerals
Hardness
Density
Tenacity
MULTIPLE CHOICE: Choose the correct answer out of the choices given for each question and fill in the corresponding circled letter
1. Which of the following properties may vary for different samples of a given mineral?
color
hardness
luster
streak
2. Which minerals has a resinous luster?
calcite
diamond
quartz
sulfur
3. Which of the following is a physical property of minerals?
chemical make-up
bonding formation
fracture
viscosity
Earth Science
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Eldon Karl M. Dumelod, LPT
4. Which carbonate mineral reacts readily with cool, dilute hydrochloric acid to produce visible bubbles of carbon dioxide gas?
Calcite
Gypsum
Plagioclase
Quartz
5. What is the hardest known mineral on earth?
Diamond
Muscovite
Native gold
Silicate
6. Which common mineral is composed entirely of silicon and oxygen?
Calcite
Diamond
Olivine
Quartz
7. What characteristics of a mineral refers to resistance to abrasion?
cleavage
hardness
luster
streak
8. Which mineral is easily soluble in water at room temperature conditions?
Diamond
Halite
Olivine
Talc
9. Which element is the most abundant in the Earth's crust by weight?
Carbon
Chlorine
Oxygen
Sodium
10. Which one of the following is NOT true for minerals?
They may be liquid, solid, or gas form.
They have a specific, internal, crystalline structure.
They have a specific, predictable chemical composition.
They can be identified by characteristic physical properties.
11. Which of the following elements bonds with silicon and forming silicates?
calcium
hydrogen
oxygen
Sodium
12. Which of the following characteristics refer to the tendency of minerals to break forming smooth flat surfaces?
cleavage
conchoidal
streak
fracture
13. Which of the following is the most common mineral on the Earth’s surface?
feldspar
mica
olivine
Quartz
Earth Science
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Eldon Karl M. Dumelod, LPT
14. Which of the following is NOT a characteristic of minerals?
possess a crystalline structure
formed by inorganic processes
definite chemical composition
either liquid or solid
15. Which of the following is the most abundant mineral group on the Earth's crust?
carbonates
oxides
silicates
sulfides
16. Which of the following refers to ability of minerals to reflect light on its surface?
Streak
luster
fluorescence
color
17. Which of the following is said to be the most unreliable (variable) diagnostic property of minerals?
luster
hardness
crystal form
color
18. On Mohs hardness scale, which is the softest mineral?
apatite
calcite
quartz
talc
19. Which one of the following is NOT one of the eight most common elements in Earth's crust?
aluminum
calcium
carbon
potassium
20. Which of the following best suits the definition of a mineral?
clastic and mafic
foliated and amorphous
naturally occurring and crystalline
organic and solution
21. Which of the following refers to an aggregate of one or more minerals?
A. compounds
C. mineraloids
B. elements
D. rock
22. Which of the following leads to formation of an igneous rock?
A. at great depth within Earth
C. by changes in mineral composition
B. by crystallization of molten rock
D. by the weathering of pre-existing rocks
23. Which of the following is produced when limestone undergoes metamorphism?
A. phyllite
C. marble
B. mica schist
D. gneiss
24. Sedimentary rocks account for about how much in the total percentage of rocks found in all continents?
A. 20
C. 50
B. 35
D. 75
25. Which of the following does NOT refer to sedimentary rocks?
may contain fossils
may be economically important
hold important clues to Earth's history
formed because of heat and pressure at depths
Earth Science
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Eldon Karl M. Dumelod, LPT
Key Question:
1. Are the minerals present in dietary
supplements and the minerals we are talking
about here the same?
Lesson 4.1
Minerals
Earth is one of the four terrestrial planets in the solar system. The geosphere, which is one of the four interacting spheres that
allow life to exist, refers to the solid earth. It is composed of rock and regolith which are essentially aggregates of various minerals.
A mineral is defined as a naturally- occurring, inorganics solid with definite chemical composition and an ordered internal
structure. Every mineral is unique, but they exhibit general characteristics.
Characteristics of Minerals
You encounter minerals every day, from the quartz inside your watch to the gemstones you wear on your fingers, and yet you
may not realize the abundant nature of minerals on Earth. Thousands of minerals have been discovered, but only about 200 are
common to the average person. Humans cannot live without minerals as they keep the human body functioning normally. People
use minerals every day within their bodies and in many industries, but minerals cannot be made by man.
Minerals Are Natural
You must find minerals in nature; substances concocted in laboratories don't qualify. Although some
laboratory products resemble minerals, they are not true minerals. Cubic zirconia and synthetic corundum,
substances masquerading as rubies or sapphires in high school graduation rings, are not true minerals because,
even though they conform to the other characteristics of minerals, they do not occur in nature. Not all naturally
occurring crystals are minerals either; opal and amber, the sap of ancient trees that have fossilized, are not minerals.
Substances called mineraloids may look like minerals but are not because they don't satisfy all the requirements for
being so.
Minerals Are Inorganic
Minerals don't belong to any class of organic compounds, which include substances such as carbohydrates,
proteins and fats made by living things. Almost all known minerals come from inorganic processes -- activities that
living things cannot carry out. A few minerals, such as pearls and the shells of some creatures, however, do originate
from organic processes. All organic substances contain carbon. Inorganic substances also can contain carbon; but
the carbon typically bonds with elements other than hydrogen and does not form long chains as it does in
carbohydrates and fats.
Minerals Are Solids
Minerals cannot be liquids or gases; they exist only as solids, a state of matter that possesses a high
amount of order. Ions, which are charged atoms, bond together to form minerals, which gives them a solid structure.
Solids have a clearly defined volume and shape, and their molecules normally cannot be compressed any further.
Their structures are rigid, meaning that the particles within the mineral don't move around. Solids can be crystalline or
amorphous. Crystalline solids such as minerals have repeating patterns, whereas amorphous solids such as glass do
not.
Definite Chemical Composition
Each mineral has its own specific combination of atoms that cannot be found in any other mineral. For
example, salt is a mineral that consists of sodium and chlorine ions bonded together in a repeating pattern.
Diamonds, on the other hand, have only one type of atom: carbon. The carbon atoms come together extremely tightly
in a type of chemical bond different from the one responsible for forming salt, making diamonds the hardest
substance on Earth. Some minerals, such as gold, silver, copper and diamond, have only one type of element in
them. The largest group of minerals contains some form of silicate, a combination of silicon and oxygen atoms.
Crystalline Structure
Minerals form crystals that contain repeated arrangements of atoms or ions. Each repeating part of a crystal
is a unit cell which takes on different shapes depending on the size of the ion or atom and how it attracts other
particles. Crystals usually take one of six common shapes. Cubic and tetrahedral forms predominate, although others
exist less commonly. Minerals have crystalline structures that form in two ways. Magma or lava -- the hot, molten
rock that comes from volcanoes -- can crystallize to form minerals. Minerals crystallize also form in the oceans when
water deposits solutes in a certain area. Crystals appear when the water evaporates.
Earth Science
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Eldon Karl M. Dumelod, LPT
Composition of Minerals
1. Silicates contain silicon (Si) and oxygen (O) tetrahedrons (SiO4-2), the two most abundant elements in the earth’s crust.
Over 90% of the common rock-forming minerals are silicates. Common silicate minerals include olivine, pyroxene,
amphibole, biotite mica, muscovite mica, plagioclase feldspar, orthoclase feldspar, and quartz.
2. Oxide minerals are made up of oxygen and one or more metals. Common oxide minerals include magnetite (Fe3O4)
hematite (Fe2O3) and limonite.
3. Sulfates contain sulfur and oxygen (SO4) combined with other elements. They usually precipitate out of water near
Earth’s surface. Common sulfate minerals include gypsum and barite.
4. Sulfides contain sulfur (S-2) and a metal. They are common ore minerals along with oxides since metals form a high
proportion of the mineral. Common sulfide minerals include galena (PbS) and pyrite (FeS2).
5. Carbonates contain carbonate (CO3), a combination of carbon and oxygen (CO3-2), combined with other elements like
calcium and magnesium to form calcite (CaCO3) or dolomite (CaMg(CO3)2).
6. Native Elements or Native Metals are minerals that form as individual elements. Gold (Au) and copper (Cu) are
examples of metallic native elements. Diamonds are a type of non-metallic native element.
7. Halides include such elements as chlorine and fluorine. Common halide minerals include halite or rock salt (NaCl) and
fluorite (CaF2).
Crystal Structure of Minerals
Crystal structure is dependent on the chemical composition of the mineral. Mineral the have similar chemical composition
often share the same crystal structure and generally belong to the same crystal system. There are 6 crystal systems used in grouping
minerals based on structure: Isometric, Hexagonal, Tetragonal, Orthorhombic, Monoclinic and Triclinic.
Isometric
The isometric crystal system is also known as the cubic system. The crystallographic axes used in this system are
of equal length and are mutually perpendicular, occurring at right angles to one another. All crystals of the isometric system
possess four 3-fold axes of symmetry, each of which proceeds diagonally from corner to corner through the center of the cubic
unit cell. Crystals of the isometric system may also demonstrate up to three separate 4-fold axes of rotational symmetry.
These axes, if present, proceed from the center of each face through the origin to the center of the opposite face and
correspond to the crystallographic axes. Furthermore, crystals of the isometric system may possess six 2-fold axes of
symmetry which extend from the center of each edge of the crystal through the origin to the center of the opposite edge.
Minerals of this system may demonstrate up to nine different mirror planes.
Examples of minerals which crystallize in the
isometric system are halite, magnetite, and garnet. Minerals of this system tend to produce crystals of equidimensional or
equant habit.
Figure 4.1.1: Isometric or Cubic crystal system
http://www.geologyin.com/2014/11/crystal-structure-and-crystal-system
Hexagonal
Minerals of the hexagonal crystal system are referred to three crystallographic axes which intersect at 120° and a
fourth which is perpendicular to the other three. This fourth axis is usually depicted vertically. The hexagonal crystal system is
divided into the hexagonal and rhombohedral or trigonal divisions. All crystals of the hexagonal division possess a single 6fold axis of rotation. In addition to the single 6-fold axis of rotation, crystals of the hexagonal division may possess up to six 2fold axes of rotation. They may demonstrate a center of inversion symmetry and up to seven mirror planes. Crystals of the
trigonal division all possess a single 3-fold axis of rotation rather than the 6-fold axis of the hexagonal division. Crystals of this
division may possess up to three 2-fold axes of rotation and may demonstrate a center of inversion and up to three mirror
planes. Minerals species which crystallize in the hexagonal division are apatite, beryl, and high quartz. Minerals of this division
tend to produce hexagonal prisms and pyramids. Example species which crystallize in the rhombohedral division are calcite,
dolomite, low quartz, and tourmaline. Such minerals tend to produce rhombohedra and triangular prisms.
Figure 4.1.2: Hexagonal crystal system
http://www.geologyin.com/2014/11/crystal-structure-and-crystal-system
Earth Science
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Eldon Karl M. Dumelod, LPT
Tetragonal
Minerals of the tetragonal crystal system are referred to three mutually perpendicular axes. The two horizontal axes
are of equal length, while the vertical axis is of different length and may be either shorter or longer than the other two. Minerals
of this system all possess a single 4-fold symmetry axis. They may possess up to four 2-fold axes of rotation, a center of
inversion, and up to five mirror planes. Mineral species which crystallize in the tetragonal crystal system are zircon and
cassiterite. These minerals tend to produce short crystals of prismatic habit.
Figure 4.1.3: Tetragonal crystal system
http://www.geologyin.com/2014/11/crystal-structure-and-crystal-system
Orthorhombic
Minerals of the orthorhombic crystal system are referred to three mutually perpendicular axes, each of which is of a
different length than the others. Crystals of this system uniformly possess three 2-fold rotation axes and/or three mirror planes.
The holomorphic class demonstrates three 2-fold symmetry axes and three mirror planes as well as a center of inversion.
Other classes may demonstrate three 2-fold axes of rotation or one 2-fold rotation axis and two mirror planes. Species which
belong to the orthorhombic system are olivine and barite. Crystals of this system tend to be of prismatic, tabular, or acicular
habit.
Figure 4.1.4: Tetragonal crystal system
http://www.geologyin.com/2014/11/crystal-structure-and-crystal-system
Monoclinic
Crystals of the monoclinic system are referred to three unequal axes. Two of these axes are inclined toward each
other at an oblique angle; these are usually depicted vertically. The third axis is perpendicular to the other two. The two
vertical axes therefore do not intersect one another at right angles, although both are perpendicular to the horizontal axis.
Monoclinic crystals demonstrate a single 2-fold rotation axis and/or a single mirror plane. The holomorphic class possesses
the single 2-fold rotation axis, a mirror plane, and a center of symmetry. Other classes display just the 2-fold rotation axis or
just the mirror plane. Mineral species which adhere to the monoclinic crystal system include pyroxene, amphibole, orthoclase,
azurite, and malachite, among many others. The minerals of the monoclinic system tend to produce long prisms.
Figure 4.1.5: Monoclinic crystal system
http://www.geologyin.com/2014/11/crystal-structure-and-crystal-system
Triclinic
Crystals of the triclinic system are referred to three unequal axes, all of which intersect at oblique angles. None of the
axes are perpendicular to any other axis. Crystals of the triclinic system may be said to possess only a 1-fold symmetry axis,
which is equivalent to possessing no symmetry at all. Crystals of this system possess no mirror planes. The holomorphic class
demonstrates a center of inversion symmetry. Mineral species of the triclinic class include plagioclase and axinite; these
species tend to be of tabular habit.
Figure 4.1.6: Triclinic crystal system
http://www.geologyin.com/2014/11/crystal-structure-and-crystal-system
Earth Science
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Eldon Karl M. Dumelod, LPT
Physical Properties of Minerals
Crystal Form and Habits
Crystal habit is the tendency for specimens of a mineral to repeatedly grow into characteristic shapes. These
shapes are influenced by the atomic structure of the mineral, but they can also be influenced by the environment of crystal
growth. Regardless of influence, crystal habit shapes are characteristic of the mineral and displayed by many specimens of
that mineral. Some examples are the following:
 Botryoidal: malachite and hematite
 Banded: rhodochrosite and fluorite
 Striated: tourmaline and beryl
 Acicular: rutile, millerite, and tourmaline
 Dendritic: copper and pyrolusite
 Nodular: quartz, azurite, and hematite
 Prismatic: quartz, beryl, and tourmaline
Crystal habit is an external shape displayed by an individual crystal, but more often it is an external shape displayed
by an aggregate of crystals. Crystal habit names are often adjectives that help convey the shape of a crystal or a group of
crystals. Bladed, cubic, fibrous, granular, prismatic, and radiating are names of crystal habits that quickly convey a generalized
geometric appearance. Other crystal habit names are less familiar, but once a person learns the name it can easily be applied
to mineral specimens to which that habit applies.
Many minerals have characteristic habits which can serve as clues to their identification. However, many minerals do
not have a characteristic external shape, and the name of this habit is “massive”. In addition, most specimens of any mineral
do not display a characteristic habit. In rare instances, one mineral might replace crystals of another mineral to assume its
characteristic habit. Crystals formed in this situation are known as pseudomorphs.
Crystal form is a concept similar to “crystal habit”. A crystal form is a solid crystalline object that is bounded by a set
of flat faces that are related to one another by symmetry. Euhedral crystals are the best representations of a crystal form.
Examples include:
 Cubic crystals of halite or fluorite
 Octahedral crystals of diamond or fluorite
 Dodecahedral crystals of garnet
 Hexagonal crystals of quartz or corundum
Crystal Habits and Forms Examples
Acicular crystals have a needle-like shape
that tapers to a point or a blunt
termination. Many acicular crystals can
be clustered to produce fan-shaped or
radially-shaped aggregates. The name
acicular should be used when the length
of an individual crystal is much greater
than its width or diameter. Mineral
examples include rutile, natrolite,
millerite, and gypsum. This geode found in
Kentucky contains thin needle-like crystals
of millerite. This specimen is also a good
example of the geodic habit.
www.iRocks.com
Earth Science
Banded minerals have narrow layers or
bands of different color and/or texture.
These may be a response to changes in
the composition of the growth liquid,
the sedimentary process, or other
conditions. Mineral examples: quartz
(agate), malachite, rhodochrosite, and
fluorite. The photo above shows
rhodochrosite cabochons that display a
banded habit. In one of the cabochons,
the banded habit is actually an internal
feature of a stalactitic habit. The
cabochons were cut from material
mined in Argentina, and the cabochon
on the left is about two centimeters in
length.
www.geology.com
Bladed crystals are elongated. They are
much longer than they are wide, and
their width exceeds their depth. They
are shaped like a straight sword or knife
blade. Their ends sometimes taper to a
point. They might exist as single
crystals, a cluster of many parallel
crystals, or radiating clusters of crystals.
Mineral examples: kyanite, actinolite,
and stibnite. These blue crystals of
kyanite have a bladed habit. Kyanite
crystals are interesting because they
have a hardness of 4.5 to 5 parallel to
the length of their blades, and a
hardness of 6.5 to 7 across the width of
their blades. This specimen is
approximately seven centimeters across.
www.geology.com
13
Eldon Karl M. Dumelod, LPT
Botryoidal (also known as globular or
mammillary) is derived from the Greek
word botrys, which means "bunch of
grapes". This habit name is used for
crystal aggregates that have a globular or
rounded shape. Mineral examples:
hematite,
malachite,
smithsonite,
hemimorphite,
variscite,
quartz
(chalcedony), quartz (grape agate), and
goethite. These green crystal aggregates
of malachite have a botryoidal habit. This
view spans an area of the specimen
approximately five millimeters across.
www.iRocks.com
Dendritic crystals form a branching
pattern, much like the branches of a tree,
the veins in a leaf, or the branching
pattern of streams in a drainage basin.
Mineral examples: copper, pyrolusite, and
other manganese oxide minerals. These
crystals of pyrolusite formed on a bedding
surface of a piece of lithographic
limestone collected near Solnhofen,
Germany.
www.geology.com
Drusy is a habit name used for a surface
that is covered with small crystals. The
crystals themselves are referred to as a
druse. Quartz is the most common
mineral found as a druse. Other mineral
examples: uvarovite garnet, malachite,
and azurite. The rock in the photo above
has a drusy surface because it is covered
by a layer of uvarovite crystals.
www.iRocks.com
Earth Science
Columnar crystals are long prisms with
enough width that the name acicular (or
needle-like) does not apply. A single
"column" might contain multiple parallel
crystals. Mineral examples: calcite,
tourmaline, and gypsum. These enormous
crystals of selenite gypsum have a
columnar habit. They are in the "Cave of
the Crystals" cavern, Chihuahua, Mexico
(a person in the lower-right quadrant of
the photo serves as scale). These are
some of the largest well-formed crystals
in the world.
www.Wikimedia.com
Dodecahedral garnet crystals about four
millimeters across, from Idaho. A
dodecahedron is any polyhedron with
twelve flat faces. The dodecahedron is
one of the most common forms for garnet
crystals.
www.geology.com
Fibrous is a habit name used when
minerals occur in very fine fiber-like
crystals. They are often so fine that they
look like fine hair. The habit also includes
aggregates made up of a large number of
parallel or radial fibers. Mineral
examples:
actinolite,
chrysotile,
serpentine, and tremolite. The actinolite
crystals on this rock have a fibrous habit.
Because of their fibrous shape (a roughly
1:20 aspect ratio) and properties, fibrous
crystals of actinolite are regulated as
asbestos.
www.CreativeCommons.com
14
Cubic crystals of pyrite. Fluorite and halite
are two common minerals with a cubic
shape. Cubes have six square faces and
four-fold rotational symmetry around
three axes. The photo shows cubic crystals
of pyrite from Navajún, Rioja, Spain, that
have grown in a marlstone. Specimen is
approximately 4 inches (9.5 centimeters)
across.
www.CreativeCommons.com
Doubly terminated is a name used for a
prismatic crystal that has a natural
termination on both ends. Normally,
crystals have a termination on one end because the other end of the crystal was
attached to the wall of a geode, the roof
of a cavern, or a surface that it was
growing on. The doubly terminated
crystals shown in the photo above are
composed of quartz and are known as
"Herkimer diamonds" (a misnomer).
www.geology.com
Foliated (also known as Micaceous) is a
sheet-like or layered structure. Minerals
with a foliated habit are often able to be
split into thin sheets. Members of the
mica family are the best examples of a
foliated habit. Mineral examples:
muscovite, biotite, and chlorite. This
specimen of muscovite exhibits a foliated
habit. The mineral can easily be separated
into very thin sheets. The specimen is
approximately 5 centimeters across.
www.geology.com
Eldon Karl M. Dumelod, LPT
Geodic is a habit in which mineral
aggregates form a rounded or oblate
mass by crystallization on the inside walls
of a cavity. Concentric bands or layers of
mineral crystals subsequently develop,
gradually infilling the cavity without
infilling it completely and with a crystallined central void. The specimen in the
photo is a geode formed by the
precipitation of banded agate to form the
external wall and initial layers. The center
of the geode is lined with quartz crystals.
www. iStockphoto.com
Granular is the habit of a crystalline
aggregate composed of many rounded or
equant anhedral crystals of approximately
the same size. The crystals might be loose
with no interstitial material, or they might
be interlocking such as calcite grains in a
marble. Mineral examples: olivine,
bornite, and scheelite. The photo shows a
specimen of granular olivine in basalt. The
olivine is in small rounded grains of about
2 to 4 millimeters in size with no
interstitial material.
www.geology.com
Prismatic is a habit name for minerals that
form in elongated crystals with opposite
faces normally parallel to one another. The
crystals are often striated along their
length (as in tourmaline) or across their
width (as in quartz). Mineral examples:
tourmaline, quartz, beryl, hornblende,
augite, diopside, and topaz. Shown in the
photo above are prismatic crystals of
colorful tourmaline from Afghanistan with
striations parallel to their long axis. The
largest specimen in this photo is about
three centimeters in length.
www.geology.com
Stalactitic is a habit name used for
specimens that have formed as stalactites
or stalagmites. The crystals often grow
downwards or upwards in a cavity or
cavern, yet they have a radial internal
cross section. Mineral examples: calcite,
malachite, goethite, and quartz. The
photo shows a geode with stalactites of
gem silica (inverted) from the Inspiration
Mine, Gila County, Arizona.
www.iRocks.com
Nodular is the name of a habit in which
mineral crystals grow to form rounded or
bulbous structures. The crystals are
usually arranged in a radial structure
within the nodule, even though the
nodules may exhibit concentric banding.
In the concentric banding, each layer is
composed of crystals growing up and
outward from the layer immediately
below. Mineral examples: quartz (agate),
azurite, hematite, realgar, and variscite. A
nodule of variscite (bright green),
crandallite (canary yellow), wardite (gray)
and montgomeryite (dark green).
www.iRocks.com
Striations are fine, slightly indented lines
that are present on the faces of some
crystals. They always parallel a
crystallographic axis and one of the edges
of that crystal face. Mineral examples:
pyrite, tourmaline, quartz, feldspar,
euclase, and topaz. The photo shows a
crystal of blue euclase with striations on
its faces that parallel the long axis of the
crystal. This specimen is also a good
example of the prismatic crystal habit.
www.iRocks.com
Cleavage, Fracture and Parting
Cleavage, fracture, and parting all have to do with the positioning of atoms in a mineral and how it breaks when put
under stress. (These three properties are listed on the same page due to their comparability, but are each individually
discussed).
Cleavage
In mineral terms, cleavage describes how a crystal breaks when subject to stress on a particular plane. If
part of a crystal breaks due to stress and the broken piece retains a smooth plane or crystal shape, the mineral has
cleavage. A mineral that never produces any crystallized fragments when broken off has no cleavage.
Cleavage is often measured by three factors:
1) Quality of Cleavage
Quality of cleavage can be categorized into five qualities:
 Perfect Cleavage- Minerals with perfect cleavage will cleave without leaving any rough
surfaces; a full, smooth plane is formed where the crystal broke.
Earth Science
15
Eldon Karl M. Dumelod, LPT
Good Cleavage - Minerals with good cleavage also leave smooth surfaces, but often leave
over minor residual rough surfaces.
 Poor Cleavage - minerals with poor cleavage, the smooth crystal edge is not very visible,
since the rough surface is dominant.
 Indiscernible (Indistinct) Cleavage - If a mineral exhibits cleavage, but it so poor that it is
hardly noticeable, it has "indiscernible" cleavage.
 None Cleavage - Minerals with no cleavage never exhibit any cleavage, thus broken
surfaces are fractured and rough.
Categorization of cleavage qualities is not scientifically affirmed. The above categorization is
used by most mineral references, but some guides categorize cleavage in three or four groups, and may
give them different names, such as "excellent" and "distinct".

2) Number of Sides Exhibiting Cleavage
Number of Sides Exhibiting Cleavage:
Many minerals exhibit cleavage only on one side, and some may exhibit different quality
cleavage on different crystal sides. The following criteria may be expected when analyzing the
cleavage of any particular mineral:
 One Direction
 Two Directions
 Three Directions
 All Directions
These identify how many "directions", or planes, the crystal is exhibiting the cleavage on.
Each direction signifies the two opposite sides of a three-dimensional figure, (since opposite sides
will always exhibit the same cleavage properties). If a mineral has cleavage in three directions,
then every side of the mineral has cleavage (i.e. length, width, and height). If a mineral occurs in
modified crystals with more than six sides (i.e. an octahedron) and exhibits cleavage on all the
sides, than it has cleavage in "all directions".
Combining the cleavage level together with the number of sides will measure the cleavage
of a mineral. For example, if a mineral has Good Cleavage, Two Directions, this means that it
has good cleavage on four out of six sides (while the other two sides exhibit no cleavage). If a
mineral has Perfect Cleavage, One Direction; Poor Cleavage, Two Directions, this means that
the mineral has perfect cleavage on two sides, and poor cleavage on the other four.
3) Cleavage Habit
Different habits of cleavage exist on different minerals, depending on their mode
of crystallization. These forms of cleavage are:
(a) Mica
(b) Galena
(c) Fluorite
(d) Aegirine
(e) Barite
(f) Calcite
Figure 4.1.7. Cleavage Habit: (a.) Basal, (b.) Cubic, (c.) Octahedral, (d.) Prismatic, (e.) Pinicoidal, (f.) Rhombohedral
www.sciencesource.com
a. Basal Cleavage:
Cleavage exhibited on a horizontal plane of the mineral by way of its base. Minerals
with basal cleavage can sometimes be "peeled". An example of basal cleavage are the mica minerals.
Earth Science
16
Eldon Karl M. Dumelod, LPT
b. Cubic cleavage:
Cleavage exhibited on minerals of the isometric crystal system that are crystallized as cubes. In this
method of cleavage, small cubes evenly break off of an existing cube. An example is Galena.
c. Octahedral cleavage:
Cleavage exhibited on minerals of the isometric crystal system that are crystallized as octahedrons. In
this method of cleavage, flat, triangular "wedges" peel off of an existing octahedron.
An example is Fluorite.
d. Prismatic cleavage:
Cleavage exhibited on some prismatic minerals in which a crystal cleaves as thin, vertical, prismatic
crystals off of the original prism. An example is Aegirine.
e. Pinicoidal cleavage:
Cleavage exhibited on some prismatic and tabular minerals in which a crystal cleaves on
the pinacoidal plane, which is the third dimension aside from the basal and prismatic sides.
An example is Barite.
f.
Rhombohedral cleavage
Cleavage exhibited on minerals crystallizing in the hexagonal crystal system as rhombohedrons, in
which small rhombohedrons break off of the existing rhombohedron. An example is Calcite.
Parting
Parting is characteristically similar to cleavage. It is easily confused with cleavage, and it may be present on
minerals that do not exhibit any cleavage. There are two causes of parting:
1. Two separate pressures pushed toward the center of a crystal after its formation, causing the crystal
interior to evenly dislodge on a flat, smooth plane.
2. Twinned crystals that separated from one another, leaving a flat, smooth plane.
With enough perception, a distinction can be made between parting and cleavage. If fracture marks are
present on a crystal in addition to a cleaved plane, the "cleaved" surface is usually the result of parting, not cleavage.
An outline of a crystal etched in a mineral is also the result of parting, in the form of twinned crystals that separated.
In general, one need not worry about confusing parting with cleavage. Parting is uncommon, and it can
usually be determined by the distinguishing characteristics mentioned above.
Fracture
Fracture is the characteristic mark left when a mineral chips or breaks. Cleavage and fracture differ in that
cleavage is the break of a crystal face where a new face (resulting in a smooth plane) is formed, whereas fracture is
the "chipping" shape of a mineral. All minerals exhibit a fracture, even those that exhibit cleavage. If a mineral with
cleavage is chipped a certain way, it will fracture rather than cleave. There are several terms to describe the various
mineral fractures:







Conchoidal - Fracture resembling a semicircular shell, with a smooth, curved surface. An example of
conchoidal fracture can be seen in broken glass. (This fracture is also known as "shelly" in some
reference guides.)
Uneven - Fracture that leaves a rough or irregular surface.
Hackly - Fracture that resembles broken metal, with rough, jagged, points. True metals exhibit this
fracture. (This fracture is also known as "jagged".)
Splintery - Fracture that forms elongated splinters. All fibrous minerals fall into this category.
Earthy or crumbly - Fracture of minerals that crumble when broken.
Even or smooth - Fracture that forms a smooth surface.
Subconchoidal - Fracture that falls somewhere between conchoidal and even; smooth with irregular
rounded corners.
Some references may describe additional fractures not mentioned above, but those terms are either
synonymous or simply used as a verbal depiction of the authors inference.
Almost all minerals have a characteristic fracture. Some minerals of the same species may exhibit a
different fracture, but this is rare.
Earth Science
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Eldon Karl M. Dumelod, LPT
Luster describes how a mineral reflects light -- how brilliant or dull it is. The terms applied to luster are:
a. Metallic - minerals that exhibit a metallic luster are opaque and reflective, like a metal. Metal elements, most sulfides,
and some oxides belong in this category.
b. Submetallic- for a mineral to fall in this category, it must be opaque to nearly opaque and reflect well. Thin splinters
of submetallic minerals are translucent
c. Vitreous- this luster accounts for about 65 percent of minerals. Vitreous luster has reflective properties similar to
glass. Most of the silicates, carbonates, phosphates, sulfates, halides, and hydroxides have a vitreous luster.
d. Adamantine- transparent or translucent minerals with a very high refractive index, which means they give off a
brilliance or shine.
e. Resinous- this describe the luster of many yellow, dark orange, or brown minerals with slightly high refractive
indexes -- honey like, but not necessarily the same color.
f.
Silky- minerals with a silky luster are the result of the mineral having a very fine fibrous structure. The mineral
displays similar optical properties to silk cloth.
g. Pearly- a play of colors, like that of oil slick on water. Pearly luster is usually the result of many partly formed
cleavage cracks parallel and below the reflecting surface of a mineral.
h. Greasy- if a mineral appears as if coated with grease, it is said to have a greasy luster.
i.
Waxy- mineral appears coated with wax
j.
Earthy, Dull- minerals which exhibit very poor luster. Most of these minerals have a rough or porous surface
(a) Metallic
(f) Silky
(b) Submetallic
(g) Pearly
(c) Vitreous
(h) Greasy
(d) Adamantine
(e) Resinous
(i) Waxy
(j) Dull
Figure 4.1.8. Mineral Luster: (a.) Gold, (b.) Rutile, (c.) Quartz, (d.) Diamond, (e.) Sphalerite, (f.) Serpentine, (g.) Labradorite,
(h.) Graphite, (i.) Turquoise, (j.) goethite
www.fineminerals.com
Tenacity
Tenacity is a minerals reaction to certain stress, such as crushing, bending, breaking, or tearing. There are different
reactions to each type of stress. Since tenacity is composed of different reactions to different stresses, it is possible for a
mineral to have more than one form of tenacity. There are different forms of tenacity, and each one must be tested separately.
They are:
 Brittle - If a mineral is hammered and the result is a powder or small crumbs, it is considered brittle.

Sectile minerals can be separated with a knife into thin slices.

Malleable - If a mineral can be flattened by pounding with a hammer, it is said to be malleable.

Ductile - A mineral that can be stretched into a wire is ductile.

Flexible but inelastic - Any mineral that can be bent, and retains the new position is flexible but inelastic.

Flexible and elastic - When these minerals are bent, they spring back to their original position.
Earth Science
18
Eldon Karl M. Dumelod, LPT
Hardness
Hardness plays a major role in identifying a mineral. It can make the identification process much simpler by
considerably narrowing a search. Hardness is defined by how well a mineral will resist scratching by another mineral. A scale
to measure hardness was invented by a mineralogist named Frederick Mohs (1822) and is still the standard scale for
measuring hardness. The scale consists of numbers one through ten; 1 being the softest and 10 being the hardest. Each
number represents a different mineral - each harder than the previous number. The 10 minerals are:
Scale
1
2
3
4
5
6
7
8
9
10
Mineral
Talc
Gypsum
Calcite
Fluorite
Apatite
Feldspar
Quartz
Topaz
Corundum
Diamond
common household item (with a fixed hardness)
fingernail (2.5)
copper penny (3.5)
wire nail (4.5)
knife blade, glass (5.5)
steel file, streak plate (6.5)
Color
Color is the most eye-catching feature of many minerals. Some minerals will always have a similar color, such as
Gold, whereas some minerals, such as Quartz and Calcite, come in all colors. The presence and intensity of certain elements
will determines a specific mineral's color. Minerals with an inherent color (i.e. all specimens of the mineral are the same color)
have essential elements in them which cause their color. Good examples are Azurite and Malachite, which have their strong
blue and green color due to their copper in their atomic structure. But there are many minerals which have slight additions of
color-causing elements in some specimens that cause it to be a different color. For example, pure Quartz (SiO2), is colorless,
whereas Amethyst, a purple variety of quartz, has its purple color caused by traces of the element iron. The amount of iron
present determines the intensity of the color.
(a) Azurite
(c) Quartz
(b) Malachite
(d) Amethyst
Figure 4.1.9. Mineral Colors: (a.) Strong Blue Color, (b.) Strong Green Color, (c.) Colorless, (d.) Purple
www.fineminerals.com
Streak
Streak is the color of a crushed mineral's powder. The color
of a mineral's powder may differ from the actual color of the mineral.
This property can be useful for mineral identification. Almost every
mineral has an inherent streak color, no matter what color the actual
mineral is. For example, Calcite occurs in many different colors,
shapes, and varieties. But every single variety of Calcite has a white
streak. A streak is useful in distinguishing two minerals with the same
color but different streak. A good example is distinguishing Gold
(yellow streak), and Chalcopyrite (black streak).
Most light colored, non-metallic minerals have a white or
colorless streak, as do most silicates, carbonates, and most
transparent minerals. The streak test is most useful for identifying
Figure 4.1.10. All quartz have the same streak.
dark colored minerals, especially metals.
www.fineminerals.com
Earth Science
19
Eldon Karl M. Dumelod, LPT
Density
Specific gravity (SG) is the measurement used to determine the density of minerals. Different minerals that have the
same volume have different weights. Specific Gravity is measured by the relative weight of the item to water. The specific
gravity value is how many times greater its weight than the same volume of water. Water has a specific gravity of 1. A mineral
with a specific gravity of 2.7 is 2.7 times heavier than water. Minerals with a specific gravity under 2 are considered light,
between 2 and 4.5 average, and greater than 4.5 heavy. Most minerals with a metallic luster are heavy. The specific gravity
can vary slightly within a mineral because of impurities. Geologists measure specific gravity with expensive laboratory tools,
such as a hydrostatic balance. There are other methods to determine specific gravity, such as using water displacement, but
this is a complicated procedure that can provide inaccurate results. Instead of testing actual specific gravity, the heft of a
specimen can be noticed. It is easy to notice a very light specimen, an average specimen, and a heavy specimen (an example
could be galena with a 7.5 SG compared with graphite with a 2.2 SG).
Mineral Identification Tables
Name
Molybdenite
Graphite
Covellite
Galena
Chalcocite
Bornite
Chalcopyrite
Limonite
(Goethite)
H
11.5
1
1.5 2
2.5
2.5 3
3
3.5 4
45.5
Table 1
MINERALS WITH METALLIC TO SUBMETALLIC LUSTER
Color
Streak
Prominent
Composition
Cleavage
Lead-gray
greenish to
YES - 1 dir.
MoS2
bluish gray
(platy)
steel-gray to black
gray to black
YES - 1 dir.
C
(platy)
indigo-blue
gray to black
YES - 1 dir.
CuS
(platy)
Gray
gray
YES - 3 dir. at
PbS
90o
black to lead gray
black to lead
NO
Cu2S
gray
bronze, but with
grayish black NO
Cu5FeS4
copper-red to purplish
iridescence
brassy yellow, usually greenish
NO
CuFeS2
tarnished
black
Yellow-brown, orange- yellowish
NO
Goethite:
brown, dark brown
brown to
HFeO2
reddish
Hematite
5.5 6.5
Steel-gray to reddish
brown
reddish brown
NO
Fe2O3
Magnetite
5.5 6.5
Black
black
Fe3O4
Pyrite
66.5
Pale brassy yellow
greenish to
brownish
black
NO (but
sometimes shows
parting)
NO
FeS2
Other Properties
Greasy feel; flexible plates
Greasy feel; flexible plates
Iridescent yellow and red
High specific gravity
Brittle, high specific gravity
Also known as peacock ore
Softer than pyrite; most common copper
mineral
Mixture of rust-like iron oxides. Mostly
mineral "goethite." Earthy to metallic
luster. Stalactitic, botryoidal forms
common.
Most common iron mineral; specular
hematite variety is composed of fine
silvery flakes
Strongly magnetic; lodestone variety
shows polarity; often in octahedral (8sided) crystals
Known as "Fool's Gold." Brittle, common
in crystals, but also granular and massive
(no obvious form).
Table 4.1.1. Minerals with Metallic to Submetallic Luster
https://www.oakton.edu/user/4/billtong/eas100lab/mintable.html
Earth Science
20
Eldon Karl M. Dumelod, LPT
Name
H
Talc
1
Sulfur
12.5
1.5 2
2
Realgar
Gypsum
Sylvite
Halite
22.5
2.5
Biotite Mica
2.5
Muscovite
Mica
Bauxite
2.5
2-7
green, white,
gray
bright yellow
TABLE 2
MINERALS WITH NON-METALLIC LUSTER
Streak
Luster
Prominent
Composition
Cleavage
white
pearly or
YES - 1 dir.
Mg3Si4010(OH)2
greasy
(Platy)
yellow
pearly
none
S
red to orange
orange-red
resinous
colorless; white,
gray, yellowish
white
vitreous
Colorless, white,
often reddish
Colorless, blue,
yellow-blue
Black, dark
green, or brown
Colorless, gray,
or green
white to brown
white
vitreous
YES - 1 dir.,
GOOD
Only obvious in
the selenite
variety - 3 dir.
(rhombic)
YES - 3 dir. at 90o
white
vitreous
YES - 3 dir. at 90o
gray to
white
white
vitreous or
pearly
vitreous
white
earthy-dull
YES - 1 dir.
(sheets)
YES - 1 dir.
(sheets)
NO
colorless or
white; impurities
may discolor it
yellow or brown
Colorless, white;
impurities may
discolor it
brown, red, or
yellow
White, gray,
brown, pink
white
vitreous
YES - 3 dir., not
at 90o (rhombic)
CaCO3
white
vitreous
YES - 2 dir. (seen
in crystalline
forms)
BaSO4
white
vitreous to
pearly
YES, but not
always obvious
(rhombic).
Not obvious in
rock masses
Color
AsS
CaSO4.2H2O
KCl
NaCl
K(Mg,Fe)3
(AlSi 3O10)(OH)2
Kal2(AlSi 3O10)
(OH)2
Mixture of
AlO(OH), Al(OH 3,
and HAlO2
Calcite
3
Barite
33.5
Dolomite
33.5
Malachite
3.5 4
bright green
pale green
velvety, silky
or dull
Sphalerite
3.5 4
dark brown or
black to yellow
light yellow
to brown
resinous to
sub-metallic
YES - 6 dir. (all 6
directions not
always obvious)
ZnS
Fluorite
4
colorless, white,
yellow, purple,
blue, green
white
vitreous
YES - 4 dir. (all 4
directions not
always obvious)
CaF2
Apatite
5
shades of
yellow, green,
blue, brown
Yellow-brown,
orange-brown,
dark brown
Red and reddish
brown
white
vitreous
Not obvious indistinct
yellowish
brown to
reddish
reddish
brown
earthy, dull
NO
Goethite: HfeO2
dull to submetallic
NO
Fe2O3
Limonite
(Goethite)
45.5
Hematite
5.5.6.5
CaMg(CO3 ) 2
Cu2(CO3)(OH)2
Ca5(PO4) 3
(F,Cl,OH)
Augite
(pyroxene)
6
dark green to
black
gray
vitreous
YES - 2 dir. at
nearly 90o
complex silicate
Hornblende
(amphibole)
6
black, dark
green, or brown
grayishwhite
vitreous
complex silicate
Olivine
6
olive green or
brownish
white or
gray
vitreous to
adamantine
YES - 2
directions, ith
angles at 56o and
24o
Not obvious indistinct
Earth Science
(Mg,Fe) 2 SiO4
Other Properties
Called "soapstone." Flexible
plates, very soft
low melting temperature
Sectile; yellow powder
common on surface
3 common varieties:
-selenite: clear, transparent
-satin spar: fibrous, silky
-alabaster: granular, sugary
Bitter taste
Salty taste, dissolves easily
in water
Flexible and elastic sheets
Flexible and elastic sheets
Mixture of 3 clay minerals:
Boehmite, Gibbsite, and
Diaspore.
Earthy odor when breathed
on.
Effervesces vigorously with
cold dilute hydrochloric acid.
Transparent calcite shows
double refraction.
High specific gravity (4.5).
Ground-up barite is used as
an weighting additive for
drilling muds.
Effervesces slowly with
dilute cold hydrochloric acid,
but only when powdered
Effervesces in hydrochloric
acid. Frequently in banded,
botryoidal masses. Flame
test produces green color.
Reacts with hydrochloric
acid only when powdered to
produce hydrogen sulfide
gas.
Cubic crystals common, 8sided diamond-shaped
crystals sometimes seen;
often fluorescent
Commonly seen as 6-sided
prismatic crystals
Ordinary "rust" - a mixture of
iron oxides, composed
mostly of goethite.
Commonly appears in these
forms: oolitic, botryoidal, or
massive (no obvious form)
Most common pyroxene;
often appears as short,
stubby, prismatic crystals in
rock.
Most common amphibole;
found in many igneous
rocks. Characterized by
dark, elongated crystals
Often found as "sugary"
granular masses of dunite
21
Eldon Karl M. Dumelod, LPT
Plagioclase
feldspar
(including
Albite,
Labradorite,
etc.)
Potassium
feldspar
(Orthoclase,
Microcline)
Quartz
(crystalline
varieties)
6
Silica
(Chalcedony
varieties)
7
Garnet group
(Almandine,
etc.)
white to dark
gray
colorless
or white
vitreous
YES - 2 dir. at
nearly 90o
NaAlSi3O8 to
CaAlSi2O8
6
white, tan to
orange, red,
green, also
colorless
colorless, white,
gray, purple,
pink, black,
yellow, green
colorless
or white
vitreous or
pearly
YES - 2 dir. at
nearly 90o
colorless
vitreous
NO - shows
conchoidal
fracture
SiO2
all colors
observed
colorless
waxy or dull
usually
NO - conchoidal
fracture
predominant
SiO2
77.5
commonly red
and brown; also
yellow, pink,
green, black
colorless
to pale
brown
vitreous or
resinous
NO - but
sometimes shows
parting
silicates of Al, Ca,
Mg, Ge, Mn, Cr
Tourmaline
77.5
colorless
vitreous
Not obvious indistinct
complex silicate of
B, Al, Fe, Mg
Corundum
9
black; also
green, pink,
brown
gray, brown,
blue, red,
colorless
colorless
dull, vitreous,
adamantine
NO - but common
shows parting
7
KAlSi3O8
Al2O3
(olivine rock); gem variety
called peridot
Sodium-rich varieties are
white or light gray; calciumrich varieties are medium to
dark gray. Labradorite
variety shows blue play of
colors.
Most commonly found in
granites and pegmatites.
Varieties named by color:
Rock crystal (colorless),
Milky (white), Smoky (gray),
Amethyst (purple), Rose
(pink), Citrine (yellow); 6sided crystals common
Collectively called
"chalcedony" Agate
(banded), Jasper (red or
brown), Chert or Flint (white,
gray or black)
Commonly found in
metamorphic rocks
(transformed from
plagioclase); 12-sided
(dodeca-hedral) crystals are
common
Common in 3-sided crystals,
often prismatic with striations
or columnar structure
Often in barrel-shaped
crystals.
Clear gem varieties include:
-sapphire(blue)
-ruby (red)
-emerald (green)
Granular form is called
emery
Table 4.1.2. Minerals with Non- Metallic Luster
https://www.oakton.edu/user/4/billtong/eas100lab/mintable.html
MULTIPLE CHOICE: Choose the correct answer out of the choices given for each question and fill in the corresponding circled letter
1. Which of the following properties may vary for different samples of a given mineral?
A. color
C. luster
B. hardness
D. streak
2. Which minerals has a resinous luster?
A. calcite
B. diamond
C. quartz
D. sulfur
3. Which of the following is a physical property of minerals?
A. chemical make-up
B. bonding formation
C. fracture
D. viscosity
4. Which carbonate mineral reacts readily with cool, dilute hydrochloric acid to produce visible bubbles of carbon dioxide gas?
A. Calcite
C. Plagioclase
B. Gypsum
D. Quartz
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Eldon Karl M. Dumelod, LPT
5. What is the hardest known mineral on earth?
A. Diamond
B. Muscovite
C. Native gold
D. Silicate
6. Which common mineral is composed entirely of silicon and oxygen?
A. Calcite
B. Diamond
C. Olivine
D. Quartz
7. What characteristics of a mineral refers to resistance to abrasion?
A. cleavage
B. hardness
C. luster
D. streak
8. Which mineral is easily soluble in water at room temperature conditions?
A. Diamond
C. Olivine
B. Halite
D. Talc
9. Which element is the most abundant in the Earth's crust by weight?
A. Carbon
C. Oxygen
B. Chlorine
D. Sodium
10. Which one of the following is NOT true for minerals?
A. They may be liquid, solid, or gas form.
B. They have a specific, internal, crystalline structure.
C. They have a specific, predictable chemical composition.
D. They can be identified by characteristic physical properties.
11. Which of the following elements bonds with silicon and forming silicates?
A. calcium
C. oxygen
B. hydrogen
D. Sodium
12. Which of the following characteristics refer to the tendency of minerals to break forming smooth flat surfaces?
A. cleavage
C. streak
B. conchoidal
D. fracture
13. Which of the following is the most common mineral on the Earth’s surface?
A. feldspar
C. olivine
B. mica
D. Quartz
14. Which of the following is NOT a characteristic of minerals?
A. possess a crystalline structure
B. formed by inorganic processes
C. definite chemical composition
D. either liquid or solid
15. Which of the following is the most abundant mineral group on the Earth's crust?
A. carbonates
C. silicates
B. oxides
D. sulfides
16. Which of the following refers to ability of minerals to reflect light on its surface?
A. Streak
C. fluorescence
B. luster
D. color
17. Which of the following is said to be the most unreliable (variable) diagnostic property of minerals?
A. luster
C. crystal form
B. hardness
D. color
18. On Mohs hardness scale, which is the softest mineral?
A. apatite
B. calcite
C. quartz
D. talc
19. Which one of the following is NOT one of the eight most common elements in Earth's crust?
A. aluminum
C. carbon
B. calcium
D. potassium
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Eldon Karl M. Dumelod, LPT
20. Which of the following best suits the definition of a mineral?
A. clastic and mafic
B. foliated and amorphous
C. naturally occurring and crystalline
D. organic and solution
21. Which of the following refers to an aggregate of one or more minerals?
A. compounds
C. mineraloids
B. elements
D. rock
22. Which of the following leads to formation of an igneous rock?
A. at great depth within Earth
B. by crystallization of molten rock
C. by changes in mineral composition
D. by the weathering of pre-existing rocks
23. Which of the following is produced when limestone undergoes metamorphism?
A. phyllite
C. marble
B. mica schist
D. gneiss
24. Sedimentary rocks account for about how much in the total percentage of rocks found in all continents?
A. 20
C. 50
B. 35
D. 75
25. Which of the following does NOT refer to sedimentary rocks?
A. may contain fossils
B. may be economically important
C. hold important clues to Earth's history
D. formed because of heat and pressure
If your score is….
20- 25 Very Good! You may still read the module but you are already knowledgeable
with the topics that we are to discuss.
10- 19 Good! Go over the items that you find difficult and then you may proceed to
the lessons in this module that you don’t understand.
0-9
Earth Science
Do not worry about your score. This module is designed for you to understand
all about minerals. So, what are you waiting for? Start your journey. Turn to the
next page.
24
Eldon Karl M. Dumelod, LPT
Check one of the boxes describing how the lesson helped you attain the focus points intended for
the lesson. Based on your response, I will present you with a short assessment to check what
reinforcement or extension activities can be used to further enhance your understanding. The points
listed below your choice will be added to your overall score for this unit.
Fair
(5 points)
How did this lesson help you in….
Better
(8 points)
Best
(10 points)
Discuss the different characteristics of a mineral
Identify common rock-forming minerals using their
physical and chemical properties.
Books
Cadiz, A. P., Pascual B.C.,(2017). Fundamentals of Earth and Life Science for Senior High School.
Manila, Philippines: MindShapers Company, Inc.
Cadiz, A. P., Macasil, T.D., & Villanoy, F.M. (2016). Fundamentals of Earth Science. Manila,
Philippines: MindShapers Company, Inc.
Cortez, S. L., & Sia, D.S., (2016). Earth and Life Science. Manila, Philippines: Sibs Publishing
House, Inc.
Salandanan, G. G., Faltado, R.E., Lopez, M.B., (2016). Earth and Life Science. Manila, Philippines:
Lorimar Publishing, Inc.
Vengco, G. V., & Religiosol, F.T., (2016). Earth and Life Science. Manila, Philippines: Phoenix
Publishing House, Inc.
Internet:
Dinh. H. (2018), 5 Characteristics of Minerals. Sciencing. retrieved October 19, 2020 from
https://sciencing.com/five-characteristics-mineral-23695.html
Betss, J. (2017), Fine Minerals. retrieved October 19, 2020 from https://www.minerals.net.html
King, H. (2020), Crystal Habits and Forms of Minerals and Gems. retrieved October 19, 2020 from
https://geology.com/minerals/crystal-habit/.
For inquiries or feedback, please write or call:
Our Lady of the Pillar College- Cauayan, Inc.
San Fermin, Cauayan City, Isabela, Philippines
Telefax: (072) 652-1748
Cellphone Number: 0997 072 4633
Email Address: olpccseniorhigh@gmail.com
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Eldon Karl M. Dumelod, LPT