Q1/W2

SHS

Earth Science

Quarter 1
Learning Activity Sheet 2
Classifying Rocks
Important Minerals
Negros Occidental High School
Government Property
NOT FOR SALE
 EARTH SCIENCE
This LAS was designed and written with you in mind. It is here to help you master the nature of Earth
Science. The scope of this module permits it to be used in many different learning situations. The
language used recognizes the diverse vocabulary level of students. The lessons are arranged to
follow the standard sequence of the course.

Earth Science Activity Sheet No. 1

I. Learning Competencies
1. Classify rocks into igneous, sedimentary, and metamorphic.
2. Identify the minerals important to society

II. Background Information for Learners

The Earth’s crust is made up of rocks. Just as minerals are the building blocks of rock, rocks are
also the building blocks of Earth's LITHOSPHERE (crust and mantle down to a depth of about
100 km), ASTHENOSPHERE (although this layer, in the depth range from about 100 to 250 km,
is partially molten), MESOSPHERE (mantle in the depth range from about 250 to 2900 km), and
even part of the CORE (while the outer core is molten, the inner core is solid). Rocks exposed at
the surface of the Earth forms the continental or oceanic crust. Many such rocks, formed beneath
the surface and now exposed at the surface, were delivered to the surface from great depths in
the crust and in rare cases from the underlying mantle. Rocks are mixtures of minerals. Some
however are made of organic materials. They come in all sizes from pebbles to very large chunks
a thousand of kilometers long.

III. Accompanying DepEd Textbook and Educational Sites

Classifying Rocks

There are three major classes of rocks: IGNEOUS, SEDIMENTARY, and METAMORPHIC, with
the following attributes:

1. Igneous — they form from the cooling of

magma deep inside the earth. They often have
large crystals (you can see them with the
naked eye).

Source:https://cdn.zmescience.com/wp-
content/uploads/2015/01/Pahoehoe_toe.jpg

Magma is the heart of any igneous rock. Magma is composed of a mixture of molten or semi-
molten rock, along with gases and other volatile elements. Magma comes mainly from two

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 places where it is formed, (1) in the asthenosphere and (2) in the base of the crust above
subducting lithosphere at a convergent plate boundary.

There are two subclasses of igneous rock, VOLCANIC (sometime called EXTRUSIVE), and
PLUTONIC (sometimes called INTRUSIVE).
• VOLCANIC ROCKS (Extrusive) form at the Earth's surface. They cool and crystallize from
magma which has spilled out onto the surface at a volcano. At the surface, the magma is
more familiarly known as LAVA.
• PLUTONIC ROCKS (Intrusive) form from magma that cools and crystallizes beneath the
Earth's surface. In a sense, this is the portion of the magma that never makes it to the
surface. For the plutonic rock to become exposed at the surface, it must be tectonically
uplifted, and the overlying material must be removed by erosion.

Composition
The great majority of the igneous rocks are composed of silicate minerals (meaning that the
basic building blocks for the magmas that formed them are made of silicon [Si] and oxygen
[O]).

The major mineralogical components of igneous rocks can be divided into two groups:
Felsic (from feldspar and silica)
Felsic minerals lack iron and magnesium, they are generally light in color. They referred to as
leucocratic. Examples are quartz, muscovite, and corundum

Mafic (from magnesium and ferrous iron)

The mafic minerals include olivine, pyroxenes, amphiboles, and biotites, all of which are dark
in color. Mafic minerals are said to be melanocratic.

https://s3-us-west-2.amazonaws.com/courses-images/wp-
content/uploads/sites/115/2016/06/23200025/467px-Statue_of_Gudea_-_MET_-
_59.2-294x300.jpg

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 Uses
Igneous rocks have a wide variety of uses. One important use is as stone for buildings and
statues.
• Diorite was used extensively by ancient civilizations for vases and other decorative artwork
and is still used for art today.
• Granite - is used both in building construction and for statues. It is also a popular choice
for kitchen countertops.
• Pumice is commonly used as an abrasive. Pumice is used to smooth skin or scrape up
grime around the house. When pumice is placed into giant washing machines with newly
manufactured jeans and tumbled, the result is “stone-washed” jeans. Ground up pumice
stone is sometimes added to toothpaste to act as an abrasive material to scrub teeth.

2. Sedimentary Rocks - Sedimentary rocks are named as such because they were once
sediment. Sediment is a naturally occurring material that is broken down by the processes of
weathering and erosion and is subsequently naturally transported (or not). Sedimentary rocks
form through the deposition of material at the Earth’s surface and within bodies of water.

Classification According to Composition:

• Clastic sedimentary rocks — small rock fragments (many silicates) that were transported
and deposited by fluids (water, bed flows). These rocks are further classified by the size
and composition of the clastic crystals included in the sedimentary rocks (most often
quartz, feldspar, mica and clay).
• Conglomerates (and breccias) — conglomerates are predominantly composed of rounded
gravel, while breccias are composed of angular (sharper) gravel.

• Sandstones — as the name says, it’s a rock made from many-sand-sized minerals and
rock grains. The most dominant mineral in sandstone is quartz because it is the most
common mineral in the Earth’s surface crust.

• Mud rocks — again, the name says it all — they’re rocks made from solidified mud. They
typically contain very fine particles and are transported as suspended particles by turbulent
flow in water or air, depositing once the flow settles.

https://cdn.zmescience.com/wp-content/uploads/2015/01/IMG_5076.jpg

Biochemical rocks — you’ll probably be surprised to find out that most limestone on the face of
the Earth comes from biological sources. In other words, most limestone you see today comes

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 from the skeletons of organisms such as corals, mollusks, and foraminifera. Coal is another
example of biochemical rock.

Some common sedimentary rocks

breccia chalk chert
claystone coal conglomerate
dolomite limestone gypsum
mudstone shale siltstone

Uses of Some Sedimentary Rocks:

• Sandstone - sandstone has been a popular building material around the world for a long
time.

• Limestone. It is used in many different ways: as a building stone, in the production of lime
(an important material to improve soil for farming), glass making, industrial carbon dioxide
and cement. Chalk is a form of limestone.

• Shale (Mudstone)-Shale can be used as a filler in the production of paint, used in brick
making and is sometimes used as a base material under roads.

3. Metamorphic Rocks form when a sedimentary or igneous rock is exposed to high pressure,
high temperature, or both, deep below the surface of the Earth. The process,
METAMORPHISM, produces fundamental changes in the mineralogy and texture of the rock.
They were either sedimentary or igneous (or even metamorphic), and they changed so much,
that they are fundamentally different from the initial rock. There are two types of
metamorphism

Contact metamorphism (or thermal metamorphism) —Contact metamorphism occurs adjacent

to igneous intrusions and results from high temperatures associated with the igneous intrusion.
Rocks are so close to magma that they start to partially melt and change their properties. The
rock produced is often a fine-grained rock that shows no foliation, called a hornfels.

Regional metamorphism (or dynamic metamorphism) — occurs over large areas and
generally does not show any relationship to igneous bodies. Most regional metamorphism is
accompanied by deformation under non-hydrostatic or differential stress conditions. Thus,

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 regional metamorphism usually results in forming metamorphic rocks that are strongly foliated,
This typically happens when rocks are deep underground and they are subjected to massive
pressure — so much so that they often become elongated, destroying the original features.
Pressure (often times with temperature) Example of this are: slates, schists, and gneisses.

Categories:
Foliated metamorphic rocks — pressure squeezes or elongates the crystals, resulting in a
clear preferential alignment. Examples are gneiss, phyllite, schist, and slate that have a
layered or banded appearance that is produced by exposure to heat and directed pressure.

Gneiss is a foliated metamorphic rock that has a banded

appearance and is made up of granular mineral grains. It
typically contains abundant quartz or feldspar minerals. The
specimen shown above is about two inches (five centimeters)
across.

Non-foliated metamorphic rocks — the crystals have no preferential alignment. Examples are
hornfels, marble, quartzite, and novaculite do not have a layered or banded appearance.

Amphibolite is a coarse-grained metamorphic rock that

has amphibole minerals such as the hornblende group as
its primary ingredient. The specimen shown is about two
inches (five centimeters) across.

Some Common Types of Metamorphic Rocks:

Anthracite is the highest rank of coal. It has been exposed to

enough heat and pressure that most of the oxygen and
hydrogen have been driven off, leaving a high-carbon
material behind. It has a bright, lustrous appearance and
breaks with a semi-conchoidal fracture. It is often referred to
as "hard coal"; however, this is a layman's term and has little
to do with the hardness of the rock.

Marble is a non-foliated metamorphic rock that is produced

from the metamorphism of limestone or dolostone. It is
composed primarily of calcium carbonate.

Quartzite is a non-foliated metamorphic rock that is produced

by the metamorphism of sandstone. It is composed primarily
of quartz.

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 Uses of Metamorphic Rocks

Quartzite and marble are the most commonly used metamorphic rocks. It is very hard and is
often crushed and used in building railroad tracks. They are frequently chosen for building
materials and artwork. Marble is used for statues and decorative items like vases. Schist and
slate are sometimes used as building and landscape materials. Graphite, the “lead” in pencils,
is a mineral commonly found in metamorphic rocks.

The rocks on Earth are constantly changing. The rock cycle Is a process by which one rock
type changes to another type.

The Processes of the Rock Cycle

Weathering & Erosion. Igneous, sedimentary, and metamorphic rocks on the surface of the
earth are constantly being broken down by weathering agents such as wind and water. Wind
carrying sand wears particles off rock. Flowing river water and crashing waves rub off all the
outer layers of rocks, leaving smooth river rocks or pebbles behind. Water seeps into the
cracks in mountain rocks, then freezes, causing the rocks to break open.

Weathering refers to the breaking down process of rocks. Erosion is the process of carrying
the broken-down particles of rocks. Eroded rock particles are carried away by wind or by rain,
streams, rivers, and oceans.

Deposition. Grains of sands and eroded sediments wash down to a river and eventually the
sea. Often the sediment builds up faster than it can be washed away, creating little islands
and forcing the river to break up into many channels in a delta.

Compaction & Cementation. As the layers of sediment stack up (above water or below), the
weight and pressure compact the bottom layers. Eventually the pressed and cemented
materials harden to become sedimentary rocks.

Metamorphism. Over very long periods of time, sedimentary or igneous rocks end up buried
deep underground, usually because of the movement of tectonic plates. When large pieces of
the Earth’s crust collide, enormous stresses build up. Because of this, some of the rocks are
forced downwards exposing these rocks to extreme levels of pressure and temperature. The
intense heat and pressure alter, and squeezes the sedimentary rock, causing the rock to
undergo a change and becomes metamorphic rock.

Rock Melting. This is the part where the solid Metamorphic rocks underground melt to become
magma. Magma is a hot liquid formed when rock partially or completely melts.

Cooling. Magma is usually less dense than the surrounding rock, so it tends to rise to higher
level of the Earth’s crust where it would cool and solidify to become igneous rock

At the surface when the igneous rock is already exposed to the open environment in the
surface of the crust it will undergo weathering, erosion and deposition starting the whole
process of rock cycle over again.

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 https://www.homesciencetools.com/content/images/assets/RockCycleChart_small-
page-001.jpg

Important Minerals

Mineral Deposits

Most people on planet Earth go through life unaware of what may be happening beneath their
feet, deep down in planet Earth, and only appreciate these processes when they experience
a geologic event such as an earthquake or volcanic eruption. However, every day, people will
use common objects and utensils that are made from minerals that form from the geologic
processes that are slowly and continuously transforming our planet. As such, mineral deposits
are extremely important resources that have been key contributors to the development of
society (https://www.sciencedirect.com/topics/earth-and-planetary-sciences/mineral-resource

Minerals are used for a large variety of purposes, either directly or processed into other useful
products (Davis, 2005b; Kesler, 1994)

Most rocks of the Earth's crust contain metals and other elements but at very low
concentrations. For example, the average concentration of Gold in rocks of the Earth's crust
is about 0.005 ppm (parts per million) which is roughly 5 grams of gold for every 1000 tons of
rock. Although valuable, extracting Gold at this concentration is not economic (the cost of
mining will be too high for the expected profit). Fortunately, there are naturally occurring
processes (geologic processes) that can concentrate minerals and elements in rocks of a
particular area.

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 The Two Types of Mineral Resources
1. Metallic Minerals
Metallic minerals are minerals which contain one or more metallic elements.
Metallic minerals occur in rare, naturally formed concentrations known as mineral deposits.
These deposits can consist of a variety of metallic minerals containing valuable metals such
as nickel (pentlandite), copper (chalcopyrite), zinc (sphalerite), lead (galena) and gold (occurs
as a native element or as a minor constituent within other minerals) that are used in all aspects
of our daily lives (https://www.mndm.gov.on.ca/en/mines-and-minerals/geoscience/metallic-
minerals).

2. Nonmetallic Minerals

Nonmetallic minerals are a special group of chemical elements from which no new product
can be generated if they are melted. Nonmetallic minerals are, for example, sand, gravel,
limestone, clay, and marble. Such materials lack metallic characteristics like good electric and
thermic conductivity, luster, rigor, and malleability; they are, however, essential for many
industries.

The nonmetallic minerals industry is best known for the production of cement, ceramics, glass,
and lime products. Thus, the range of application is quite broad, from construction materials
to sanitary ware to tableware and decorative products. The transformation of nonmetallic
minerals into these products is often an energy-intensive process, which can include several
steps, such as heating, grinding, mixing, cutting, shaping and honing
(https://www.statista.com/markets/410/topic/951/nonmetallic-mineral-products/).

The Importance of Mineral Resource

Mineral resource is the mineral deposit consisting of useful concentration that may or may not
exceed economic cost for obtaining the valuable minerals. The technological process, the needs
of the economy and prices in the market, depends on whether and when the rock/mineral
becomes raw material. For example, for road construction mineral raw material is stone
recovered from the quarry, and the stone blocks broken away from the rock mass for the
construction of stone structures or processing into polished slab. Rock bauxite is mineral raw
material for obtaining aluminum, hematite for iron, and kaolin for porcelain. Less-pure clay is
mineral raw material for manufacture of ceramics, and impure clay for production of tiles or
bricks. Ore deposits are formed in the Earth's crust by different geological processes and
accumulates minerals or ores in such quantities that it is technologically possible to mine and
economically profitable to gain. In such condition, the mineral resource becomes mineral or ore
reserve (https://www.sciencedirect.com/topics/earth-and-planetary-sciences/mineral-resource).

IV. ACTIVITIES
Formative Assessment:
Write your answers in a large-sized Study Notebook
Answers will be solicited during the Learners Teacher Engagement:

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TYPES OF ROCKS
There are three classifications of rocks: igneous, sedimentary, and metamorphic rock. Using the
lesson guide, identify what type of rocks are illustrated below based on composition.

Rock Sample Classificatio Rock Sample Classificatio

n n

Sandstone

Questions:
1. Are all rocks the same in term of composition? Why?
2. How do you determine the classification of rocks?

MINERALS IN OUR DAILY ACTIVITIES

Direction/s: List down 10 minerals that is used in our daily life/activities.

Mineral Where it can be found Usage

1. Why are these minerals important?

2. What would our life, society and economy be without these minerals?

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REFERENCES:
Teaching Guide for Senior High School. EARTH SCIENCE CORE SUBJECT. Published by the
Commission on Higher Education, 2016.
https://www.britannica.com/science/igneous-rock
https://www.zmescience.com/science/geology/types-of-rock/
https://courses.lumenlearning.com/geo/chapter/reading-uses-of-igneous-rocks/
https://www.mylearning.org/stories/rocks-at-cliffe-castle-museum/189
https://geology.com/rocks/metamorphic-rocks.shtml
https://www.ck12.org/earth-science/rock-cycle-processes/lesson/Rocks-and-Processes-of-the-
Rock-Cycle-HS-ES/
https://learning-center.homesciencetools.com/article/rock-cycle-science-lesson/
https://www.sciencedirect.com/topics/earth-and-planetary-
https://www.mndm.gov.on.ca/en/mines-and-minerals/geoscience/metallic-minerals
https://www.sciencedirect.com/topics/earth-and-planetary-sciences/mineral-resource

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