I. OBJECTIVES

At the end of this chapter, the students should be able to:

identify common rock-forming minerals using their physical and chemical properties

classify rocks into igneous, sedimentary, and metamorphic

identify the minerals important to society

describe how ore minerals are found, mined, and processed for human use

II. TOPICS

a. Minerals – Definition, Classification, Properties and Examples

b. Rocks – Its Classification and the Rock Cycle

c. Ores and Mining

III. LEARNING RESOURCES

Cabria, H., Olivar, J.T., Rodolfo, R.(2016).Exploring Life Through Science Series: Earth Science.

Quezon Ave., QC, Philippines: Phoenix Publishing House, Inc.

Lutgens, F.K., Tarbuck, E.J., Tasa, D.(2009).Earth Science,12th Edition. Jursong, Singapore:

Pearson Education, Inc.

Knocke, M.M.(2005).From Blue Moons to Black Holes: A Basic Guide to Astronomy, Outer

Space and Space Exploration. NY, U.S.A: Prometheus Books

IV. CONTENT

CHAPTER 2: Minerals and Rocks

Lesson 2.1: Minerals – Definition, Classification, Properties and Examples

As mentioned in the past chapter, one of the Earth’s subsytem is the geosphere. Geosphere

is the solid portion of the Earth which is primarily divided into three layers – the crust,

mantle and core. Crust is the outermost layer of the geosphere and are abundant in several

elements which include oxygen, silicon, aluminum, iron, calcium, sodium, magnesium,

potassium, titanium and hydrogen. The aforementioned elements are enumerated based on

their increasing abundance on the Earth’s crust. When these elements combine, they form

several compounds which ultimately serve as the building block of minerals.

Minerals are solid, inorganic and naturally occurring materials which have definite

chemical composition and orderly internal structure. Ice is an example of mineral since it

followed all the general characteristics of a mineral; however, liquid water is not a mineral

since it is not solid. Likewise, amber, pearl, coal, steel and obsidian, although they are solid,

are not considered minerals. Amber, pearl and coal came from living organisms; hence, they

are not inorganic. Steel is artificially prepared and is not naturally occurring. Obsidian – a

type of volcanic glass – has no ordered internal structure.

Primarily, minerals are classified based on their compositions. Since two of the most

abundant elements in Earth’s crust are oxygen (O) and silicon (Si), many minerals have these

components. From this perspective, minerals are generally categorized whether they have

these two elements or not. Minerals with silicon and oxygen are known as silicates while

minerals with no silicon and oxygen are known as non-silicates. Bear in mind that non-

silicates may still have silicon or oxygen, but the two elements should not coexist within the

same non-silicate mineral; otherwise, it will be classified as silicate.

ATHENEUM SCHOOL

Noveleta, Cavite

MODULE NO.

1 GRADE LEVEL

Eleven (11)

TEACHER Mr. Angelo C. Recomo LEARNING AREA

Earth Science

WEEKS Week 3 QUARTER 1

Table 1: Classification of Minerals

Types Composition/

Characteristics

Examples

Sil

ica

tes

Ferromagnesian

silicate

has iron and

magnesium, aside from

silicon and oxygen

generally darker in

color due to the

presence of iron

Biotite mica

Composition: K(Mg,Fe)3AlSi3O10(OH)2

Augite

Composition:

(Ca,Na)(Mg,Fe,Al)(Si,Al)2O6

Hornblende

Composition:

Ca2(Mg,Fe,Al)5(Si,Al)8O22(OH)2

Non-

ferromagnesian

silicate

has silicon and oxygen

but does not have iron

and magnesium

generally lighter in

color.

Talc

Composition: (Mg3Si4O10(OH)2

Muscovite mica

Composition: KAl2(AlSi3O10)(F,OH)2

Quartz

Composition: SiO2

Potassium feldspar

Composition: KAlSi3O3

Zircon

Composition: ZrSiO4

Non

-sil

ica

tes

Oxide

has elements (except

from silicon) bonded to

negatively charged

oxide (O-2) ion only.

Hematite

Composition: Fe2O3

Magnetite

Composition: Fe3O4

Ice

Composition: H2O

Sulfide

has elements (except

from silicon) bonded to

negatively charged

sulfide (S-2) ion only.

Galena

Composition: PbS

Pyrite

Composition: FeS2

Sulfate

has elements (except

from silicon) bonded to

negatively charged

sulfate (SO4-2) ion only.

Gypsum

Composition: CaSO4•2H2O

Epsomite

Composition: MgSO4•7H2O

Halide

has elements (except

from silicon) bonded to

negatively charged

fluoride (F-1), chloride

(Cl-1), bromide (Br-1) or

iodide (I-1), ions only.

Fluorite

Composition: CaF2

Halite

Composition: NaCl

Avogadrite

Composition: (K,Cs)BF2

Calomel

Composition: HgCl

Carbonate

has elements (except

from silicon) bonded to

negatively charged

carbonate (CO3-2) only.

Calcite

Composition: CaCO3

Dolomite

Composition: CaMg(CO3)2

Native metals has single metallic

element

Gold (Au)

Copper (Cu)

Aluminum (Al)

Just like any other matter, minerals have certain properties which distinguish one type

from the other. These properties are used by the mineralogist to identify an unknown mineral

sample as well as to verify the authenticity of a precious gemstone. These distinguishing

properties of minerals are the composition, crystal structure and habit, cleavage and fracture,

color and streak, luster, hardness and density.

Basic Properties of Minerals

1. Composition – this is the compound or element that makes up a specific mineral. By

knowing the composition of a mineral, mineralogist may have a good speculation about the

identity of an unknown mineral. Table 1 provides some examples of minerals and their

compositions.

2. Crystal structure and Habit – crystal is defined as a solid structure with its compositions

arranged in a repetitive manner. For example, the chemical composition of the mineral halite

is Sodium chloride (NaCl). Microscopically, the sodium and chlorine ions in halite forms a

cubic configuration. This configuration is repeated over and over, up to the macroscopic level.

This is the reason why a grain of table salt has cube shape under the microscope. Primarily,

there are seven major crystal shape or system – cubic, tetragonal, orthorhombic, monoclinic,

triclinic, hexagonal and rhombohedral. The crystal structure of a mineral are usually seen

internally.

Habit, on the other hand, is the outward appearance of a mineral. Bear in mind that a

mineral may have a hidden crystal structure when it is broken, even if its habit seems to have

no smooth pattern.

Figure 1: The Seven Major Crystal Systems [Source: ©Encyclopaedia Britannica. Retrieved from www.britannica.com.(Retrieval date: August 18, 2020)]

Figure 2: The Crystal System of Quartz [Source: ©Geology Science (2018). Quartz.Retrieved from

www.geologyscience.com]

Figure 3: The Crystal System of Halite [Source: Fernandez, S.(2018). A Crystal Method.Retrieved from

www.news.ucsb.edu]

3. Cleavage and Fracture– cleavage is defined as the breakage of minerals along planes of

weakness which results in smooth faces in the mineral’s structure.

Figure 4: Some Cleavage Patterns

Figure 5: Cleavage of Phlogopite [Source: ©Dakota Matrix Minerals. Retrieved from

www.dakotamatrix.com.(Retrieval date: August 18, 2020)]

Figure 6: Cleavage of Fluorite [Source: Retrieved from johnbetts-fineminerals.com.(Retrieval

date: August 18,2020)]

Fracture, on the other hand, is the breakage of a mineral in a pattern that does not follow

any planes. Sometimes, it may result in rough mineral surface such as the hackly fracture

which is characterized by jagged points and the earthy fracture which is characterized by

crumbly or powdery texture. However, there are fractures which apparently exhibit regular

(sometimes smooth) pattern such as the conchoidal fracture which produces a spiral pattern

similar to the conch shell and the splintery fracture which forms fibrous, elongated fragments.

Figure 7: Conchoidal Fracture of Obsidian [Source: ©Sand Atlas. Retrieved from

www.sandatlas.org.(Retrieval date: August 19, 2020)]

Figure 8: Hackly Fracture in Native Copper [Source: ©Minerals Education Coalition. Retrieved from

mineralseducationcoalition.org.(Retrieval date: August 18,2020)

4. Color and Streak– in mineralogy, color is defined as the immediate visual hue of a

mineral while streak is the visual hue of a mineral in its powder form. Streak is obtained by

scratching a mineral against a ceramic tile. The hue that a mineral created in the ceramic tile

is the streak. There are minerals which almost have the same color but have different streak.

For example, both the minerals pyrite and gold have brassy yellow color. However, a true gold

has brassy yellow streak too, while pyrite creates a black streak once it is scratched against a

ceramic tile.

Figure 9: Color and Streak of Pyrite and Gold [Source: ©Airphoto(2003). Retrieved from www.airphotona.com.(Retrieval date: August 19, 2020)]

5. Luster– this is the behavior or appearance of light as it reflects on the surface of a mineral.

Luster in mineral can be generally categorized as metallic or nonmetallic. Nonmetallic luster

includes dull, earthy, silky, greasy, resinous (like a resin), vitreous (like a glass) and

pearlescent (like a pearl).

Figure 10: Silky Luster of Actinolite [Source: Eifert, T.L.. Mineral Lusters. Retrieved from

www.geologyfortoday.com.(Retrieval date: August 19, 2020)]

Figure 11: Metallic Luster of Pyrite [Source: Eifert, T.L.. Mineral Lusters. Retrieved from

www.geologyfortoday.com.(Retrieval date: August 19, 2020)]

Figure 12: Vitreous Luster of Quartz [Source: Eifert, T.L.. Mineral Lusters. Retrieved from

www.geologyfortoday.com.(Retrieval date: August 19, 2020)]

Figure 13: Earthy Luster of Azurite [Source: Eifert, T.L.. Mineral Lusters. Retrieved from

www.geologyfortoday.com.(Retrieval date: August 19, 2020)]

6. Hardness– this is the resistance of a mineral to a certain scratch or damage. The hardness

of a mineral is ascribed to the chemical bonds present on it. In mineralogy, hardness can be

measured using the Mohs hardness scale. In this scale 1 is the softest while 10 is the hardest.

As for comparison, 1 is represented by the mineral talc while 10 is represented by the mineral

diamond. Also, in this scale, some common objects that can scratch the representative

minerals are shown to provide an idea about their hardness. For example, fingernail can

easily scratch minerals with hardness less than 2.5 in Mohs hardness scale such as the

gypsum and talc; on the other hand, steel nail can easily scratch minerals with hardness less

than 6.5 in Mohs hardness scale such as the orthoclase, apatite, fluorite, etc.

Figure 14: Mohs Hardness Scale [Source: ©National Park Service. Retrieved from www.nps.gov.(Retrieval date: August 19, 2020)]

7. Specific gravity – this is the density of a mineral. The density of a mineral tells the

mass needed in order to complete one volume unit of it. For example, the density of silver is

10.49 g/mL which means that 1 milliliter of silver weighs 10.49 grams. If a person has 3

milliliter of silver, then that is equivalent to 31.47 grams (i.e., 10.49 x 3). In other words,

density provides a conversion factor between mass and volume. Density is obtained by

diving the the mass of the mineral to its volume. Sometimes, mineralogists use the water

displacement method to measure the volume of a mineral. Water displacement method is a

simple laboratory technique which uses water in a volume-measuring apparatus (e.g.,

graduated cylinder) to gauge the volume of irregularly shaped objects. In this method,

water is poured in a volume-measuring apparatus at a specific level. This level is the

initial reading of water volume. Then, the irregularly shaped object will be carefully

dropped on the water. This will cause the water to displace in higher level of the apparatus,

above the initial reading. This level is the final reading of water volume. The volume of the

irregularly shaped object is equivalent to the water that displaces in the apparatus or to

put it simply, the volume of the irregularly shaped object is equal to the difference of final

reading of water volume and initial reading of water volume (i.e., Vobject = Vfinal – Vinitial). For

example, an unknown irregularly shaped gemstone was dropped inside the graduated

cylinder with 50-mL water (initial reading). After it was dropped, the water inside the

graduated cylinder rose from 50-mL mark to 75-mL mark (final reading). Hence, the

volume of the gemstone is 25 mL (i.e., Vgemstone = 75 mL – 50 mL).

Lesson 2.2: Rocks –Classification and the Rock Cycle

In the past discussion, you learned that minerals are solid, inorganic and naturally

occurring materials which have definite chemical composition and orderly internal structure.

However, in Earth’s crust, a mineral is commonly aggregated or combined to other minerals

and forms a solid mixture known as rock. Rock is a solid aggragate of minerals. If mineral is a

pure substance, rock is considered a mixture. For example, the rock granite – the chief

component of continental crust – composes of the minerals like quartz, felsdspar, mica and

amphibole. On the other hand, basalt – the chief component of oceanic crust – composes of the

minerals like labradorite, augite, magnetite, olivine, quartz, hornblende and nepheline.

Basically, rocks can be classified into three types – igneous, sedimentary and metamorphic

rocks.

Igneous Rock

Igneous rock is a rock that is formed from hardened magma (i.e., molten rock inside the

Earth), lava (i.e., molten rock outside the Earth) or volcanic ash and dust. For any rock to turn

into an igneous rock, it should undergo the process known as melting. Igneous rock can be

categorized based on their origin and based on their compositions.

Classification based on the origin of material

1) Crystalline igneous rock- is formed from the hardened magma or lava. There are two

types of crystalline igneous rock.

a) Extrusive (Volcanic) igneous rock – a crystalline igneous rock that is formed

from hardened lava. Extrusive igneous rock cooled on the Earth’s outer surface.

b) Intrusive (Plutonic) igneous rock- a crystalline igneous rock that is formed from

hardened magma. Intrusive igneous rock cooled on the Earth’s inner crust.

Because extrusive igneous rock cools on the Earth’s outer surface which has lower

temperature than the Earth’s interior, it cools faster than intrusive igneous rock. Since

extrusive igneous rock cools easily, it becomes more stable at faster rate, having a very less

chance of it being deformed. Hence, extrusive igneous rock usually appears smoother than the

intrusive one which usually appears rough.

Figure 15: Examples of Extrusive and Intrusive Igneous Rocks [Source: Retrieved from www.web.lexington.k12.oh.us.(Retrieval date: August 19, 2020)]

2) Pyroclastic – is formed from consolidated eruption products like volcanic ash and dust.

Some examples of these are pumice, scoria and volcanic tuff.

Figure 16: Pumice [Source: ©Sandatlas. Retrieved from

www.sandatlas.org.(Retrieval date: August 19, 2020)]

Figure 17: Volcanic Tuff [Source: ©Sandatlas. Retrieved from

www.sandatlas.org.(Retrieval date: August 19, 2020)]

Classification based on the composition

Igneous rocks have two major compositions: Iron and Silicate. Others are consdered minor

composition. From this, three major classification of igneous rock based on its composition

were derived.

1) Mafic – igneous rock with more iron than silicate (usually dark-colored)

2) Felsic – igneous rock with more silicate than iron (usually light-colored)

3) Intermediate – igneous rock with approximately equal amount of iron and silicate

Each mineral comprising a rock has their own melting point. Because of this, rocks may

have varying compositions of different minerals. Geologists use the chart known as Bowen’s

reaction series to classify the type of igneous rock based on its composition.

Figure 18: Bowen’s Reaction Series [Source: ©Panchuk, K.(n.d.). Classification of Igneous Rocks.

Retrieved from www.openpress.usask.ca.(Retrieval date: August 19, 2020)]

Sedimentary Rock

Sedimentary rock is a rock that is formed from compaction or cementation of weathered and

eroded rock particles called sediments. Any type of rock can transform into sedimentary rock

through the processes such as weathering (i.e.,disintegration of rock particles into sediments),

erosion (i.e.,separation of weathered sediments from unweathered rock), compaction (i.e.,

joining together of sediments due to pressure) and cementation (i.e.,joining together of

sediments due to binding substance that “cements” the sediments together). While weathering

and erosion creates sediments, compaction and cementation bond these sediments to form the

sedimentary rock.

Primarily, sedimentary rocks may have either organic (i.e., those that came from living

organisms) or inorganic (i.e., did not came from living organism) compositions. These

compositions are known as sediments. There are different types of sediments that form

sedimentary rocks.

a) Chemical sediments – these are the rock materials that are dissolved in water such as the

salt sediments in seawater that forms the rock salt. The sedimentary rock “rock salt” is

chiefly made of the mineral halite, although there are few other minerals comprising it

such as the calcite, gypsum and anhydrite.

Figure 19: Halite mineral [Source: ©Sandatlas. Retrieved from

www.sandatlas.org.(Retrieval date: August 19, 2020)]

Figure 20: Gypsum mineral [Source: ©Encyclopaedia Britannica. Retrieved from

www.britannica.org.(Retrieval date: August 19, 2020)]

b) Clastic sediments – these are the rock materials that are mechanically weathered such as

the clay that forms the claystone, sand that forms the sandstone and silt that forms the

siltstone. Conglomerates are sedimentary rocks made of larger clastic sediments like

pebbles. Generally, the difference between the clay, silt, sand, pebble and stone are the size

of their individual particle. Clay is the smallest, followed by silt, then sand, then pebble

and the biggest is stone

Figure 21: Conglomerate [Source: ©King, H.M.(n.d.).Conglomerate. Retrieved from

www.geology.com.(Retrieval date: August 19, 2020)]

Figure 22: Shale (a compacted clay and silt) [Source: ©King, H.M.(n.d.).Shale Retrieved from

www.geology.com.(Retrieval date: August 19, 2020)]

c) Bioclastic sediments – these are the rock materials that came from living organisms such

as the shells of the mollusks and skeleton of the corals that make limestone and the

particles of dead plants and animals that make the coal. Bituminous coal are also formed

from this type of sediment. It actually originated from the fossils of prehistoric organisms.

Figure 23: Black Limestone [Source: ©King, H.M.(n.d.).Limestone. Retrieved from

www.geology.com.(Retrieval date: August 19, 2020)]

Figure 24: Bituminous Coal [Source: ©Virginia Geological and Economic Survey. Retrieved

from www.geology.com.(Retrieval date: August 19, 2020)]

Metamorphic Rock

Metamorphic rock is a type of rock that is formed from the structural change of its parent

rock. Parent rock (a.k.a protolith) is the material where a specific metamorphic rock

originated. For example the metamorphic rock quartzite originated from a sandstone – a type

of sedimentary rock – that underwent contact metamorphism. Hence, the parent rock of

quartzite is sandstone. The parent rock of anthracite coal is bituminous coal; whereas, the

parent rock of marble is limestone. Any type of rock can transform into metamorphic rock

through the application of heat and pressure. These two factors primarily cause structural

changes in rock in a process known as metamorphism. If the primary factor is heat, then it is

known as contact metamorphism; on the other hand, if the primary factor is pressure, then it

is known as regional metamorphism.

When a rock undergoes metamorphism, it may or may not form a metamorphic rock with

layers. Think of playing clays with different colors. Each individual clay represents a mineral.

If a person forms a pile of clay with different colors and pressure is applied to it, the pile will

be transformed into a clay with several layers of colors. This transformed clay represents the

metamorphic rocks and in metamorphic rock, the layers that are formed are known as

foliation. However, if the pile of clay is subjected to heat, the colors will just combine and there

will be no layers that will be formed. Hence, pressure creates foliated metamorphic rocks while

heat creates nonfoliated metamorphic rocks.

Figure 25: Quartzite [Source: ©King, H.M.(n.d.).Quartzite. Retrieved from

www.geology.com.(Retrieval date: August 20, 2020)]

Figure 26: Anthracite Coal [Source: ©King, H.M.(n.d.).Anthracite Coal. Retrieved from

www.geology.com.(Retrieval date: August 20, 2020)]

Types of Foliation

– Foliation refers to the repetitive orderly arrangement of minerals in a metamorphic rock.

There are four major types of metamorphic rock foliation.

a) Slaty – is characterized by parallel foliation of miniscule and extremely fine-grained

rock particles like clay and silt. Slaty foliation has the most invisible arrangement of

minerals and it can only be seen once the rock undergoes cleavage (i.e.,smooth

breakage of rock or mineral along its flat plane of weakness). Rocks with slaty foliation

are known as slate. The protolith of slate is shale. Slate consists of minerals like

quartz, chlorite, graphite, magnetite, kaolinite, muscovite, pyrite and biotite.

b) Phyllitic – is characterized by parallel foliation of fine-grained platy minerals like

micas. Just like the slaty foliation, phyllitic foliation creates invisible arrangement of

micas and it can only be seen once the rock undergoes cleavage; however, the minerals

in phyllitic foliation are larger than those in slate. Rocks with phyllitic foliation are

known as phyllite. The protolith of phyllite is slate. Aside from mica, phyllite also

consists of minerals like quartz, chlorite, sericite and graphite.

c) Schistose – is characterized by parallel foliation of medium-sized platy minerals like

micas. The minerals in schistose foliation are larger than those in phyllite; hence, it

has more visible arrangement of minerals as compared to the first two types of

foliation. Rocks with schistose foliation are known as schist. The protolith of schist is

phyllite. Aside from mica, schist also consists of minerals like talc, quartz, garnet,

graphite, chlorite and hornblende.

d) Gneissic- is characterized by parallel foliation of coarse-grained minerals and

alternating light and dark bands. The minerals in gneissic foliation are larger than

those in schist. Unlike the phyllite and schist, gneissic foliation occurs in metamorphic

rocks with recrystallized minerals that are not platy; hence, it tends to bear less micas

and chlorites. Rocks with gneissic foliation are known as gneiss. The protolith of gneiss

can be the igneous rock granite, or the sedimentary rock sandstone or the metamorphic

rock schist. Gneiss that originated from igneous rock are called orthogneiss while

gneiss that originated from sedimentary rock are known as paragneiss. The light bands

in gneiss are usually made of light-colored non-ferromagnesian silicates while the dark

bands are usually made of minerals with iron and magnesium such as the

ferromagnesian silicates.

Figure 27: Foliated Metamorphic Rocks [Source: ©Geology In(2020).Regional metamorphism: The Formation of Foliated Metamorphic Rock.

Retrieved from www.geologyin.com]

Bear in mind that one type of rock can be transformed into other type of rock through the

process known as the rock cycle. Rock cycle includes the geological processes such as melting,

weathering, erosion, compaction, cementation and application of heat and pressure. These

processes intertwine the three different types of rock.

Figure 28: The Rock Cycle

Lesson 2.3: Ores and Mining

Sometimes, precious and expensive minerals are locked within a specific rock. These rocks

which bear some profitable minerals are known as ores. Ores are minerals or rocks which

consists of highly profitable components. Not all minerals or rocks can become ore. A mineral

or rock is considered an ore if its chemical compositions have great uses and the concentration

of its component is high enough for it to become profitable. In some cases, rocks or minerals

have precious chemical compositions; however, the process of extracting these compositions

are more expensive than the actual profit that can be obtained. Hence, these rock or minerals

are not considered good ores. The rarity of a composition determines its market price.

Generally, the rarer the mineral or element is, the more expensive it will be. Diamond, gold

and platinum are more expensive because of their rare occurrence in nature. On the other

hand, aluminum, iron and copper are less expensive because of their natural abundance.

Primarily, the processes involved in formation of ores are cooling and crystallization,

although there are other processes that may form ores. Sometimes when magma (i.e.,molten

rock on the Earth’s interior) flows through the narrow fractures of Earth called veins, it forms

a granitic rock known as pegmatite. Some precious and rare metals seeps through the

pegmatite. As pegmatite cools and crystallizes, the precious and rare metals incorporate

themselves into the rock’s body, creating an ore. Hence, commonly, ore deposits are usually

found on or near hydrothermal solutions (i.e.,hot metal-rich fluids associated with cooling

magma bodies). When a hydrothermal solution flows in rock fracture, the resulting deposit is

known as vein deposit. Gold, silver and mercury are usually mined in vein deposits. On the

other hand, if the hydrothermal solution deposits on the entire rock mass not just on

fractures, it will produce a disseminated deposit where the metal copper is usually extracted.

Figure 29: Dessiminated vs. Vein Deposits (left) and Vein Deposit of Gold in Quartz (right) [Source of picture in right: ©James St. John(2012). Gold-quartz hydrothermal vein

(Red Mountain Mining District, Ouray County, Colorado, USA). Retrieved from www.flickr.com]

Other minerals are formed from a specific type of magma. For example, diamonds are

usually formed in kimberlite magma – a type of magma that can be found in highly

pressurized region beneath the Earth’s crust (usually 150 km deep). On the other hand,

chromites are usually found in basaltic magma – an iron-rich magma. Chromite usually sinks

at the bottom of the molten rock since it is denser than the other minerals present in basaltic

magma (Cabria, Olivar, Rodolfo, 2016)

While formation of ores with expensive metals and minerals are associated with igneous

activities, formation of ores with less expensive but economically important metals and

minerals are associated with metamorphic activities and exogenic processes (i.e., external

processes such as weathering of rocks, erosion and deposition of sediments). For example,

chrysotile (a.k.a white asbestos), marble and graphite can be formed through metamorphism.

Halite, gypsum and anhydrite are left when water evaporates out of the seawater while

laterites (i.e.,a reddish clayey soil that is rich in iron and aluminum) are formed from the

chemical weathering of some igneous rocks which are impregnated with iron and aluminum.

Below are some economically important ores.

Table 2: Some Economically Important Ores and Their Element Contents

Ores Element content Ores Element content

Bauxite Aluminum Pentlandite Nickel

Chalcopyrite Copper Pitchblende Uranium

Hematite Iron Cinnabar Mercury

Acanthite Silver Monazite Thorium

Sphalerite Zinc Chromite Chromium

Figure 30: Bauxite [Source: ©King, H.M.(n.d.).Bauxite. Retrieved from

www.geology.com.(Retrieval date: August 20, 2020)]

Figure 31: Chalcopyrite [Source: ©King, H.M.(n.d.).Chalcopyrite. Retrieved from

www.geology.com.(Retrieval date: August 20, 2020)]

Figure 32: Hematite [Source: ©King, H.M.(n.d.).Hematite. Retrieved from

www.geology.com.(Retrieval date: August 20, 2020)]

Figure 33: Acanthite [Source: ©Crystal Classics Ltd.(2016).Acanthite(Argentite).ID

no:CC10137. Retrieved from www.crystalclassics.co.uk.]

Figure 34: Sphalerite with other minerals [Source: ©Arkenstone(n.d.).Sphalerite. Retrieved from

www.iRocks.com.(Retrieval date: August 20, 2020)]]

Figure 35: Pentlandite [Source: ©U.S. Geological Survey.(n.d.).Pentlandite. Retrieved

from www.britannica.com.(Retrieval date: August 20, 2020)]

Figure 36: Pitchblende or Uraninite [Source: ©Arkenstone(n.d.).Uraninite. Retrieved from

www.iRocks.com.(Retrieval date: August 20, 2020)]

Figure 37: Cinnabar on Dolomite [Source: ©H. Zell(n.d.).Cinnabar. Retrieved from

www.geology.com.(Retrieval date: August 20, 2020)]

Ore Extraction

Ores are extracted on Earth through the systematic process of mining. Mining is a set of

procedures through which profitable underground resources like heavy metals are extracted

out of any natural geological structures such as rocks, mountains, caves, etc. Bear in mind

that mining is different from quarrying. Quarrying refers to a set of procedures through which

profitable ground resources such as sand, gravel, salt and coal are extracted out of any natural

geological structures. While mining collects expensive metals and minerals that are buried

underground, quarrying collects relatively cheap resources and minerals which are used as

construction materials.

Amidst the differences, both mining and quarrying undergo the same general steps.

Figure 38: Procedures in Mining (Source: Cabria,H.B., Olivar II, J.T. & Rodolfo, R.S.(2016).Exploring Life Through Science

Series.Quezon City, Philippines: Phoenix Publishing House, Inc., p.45)

Due to the location of the Philippines, many minerals can be mined on it. In fact,

Philippines is the 5th most mineralized country in the world, 3rd in gold reserves, 4th in copper

and 5th in nickel (Cabria, Olivar, Rodolfo, 2016).

Prospecting

•looking for a good location of ores

Drilling

•extraction of small part of ore for its characterization

Modeling

•determination of ore size and shape to apply appropriate mining method

Identifying the potential impacts

•considering the social an environmental effects of the procedures

Constructing the mine

•architects and engineers plan and construct the mining site

Ore Extraction

•the mineral is dug and extracted from the rock body mechanically

Milling

•the ore is crushed and concentrated while waste materials (tailings) are released. In gold and platinum ores, a mixture known as agua regia (mixture of Hydrochloric acid

and Nitric acid) to dissolve the pure gold or platinum.

Decommissioning

•After the depletion of minerals, the mine will be closed for rehabilitation

V. REFLECTION

Complete the sentence below based on your learning experience in this lesson. This is not

graded so be honest in answering this.

In this chapter, I learned that ____________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________

________________________________________________________________________________________