ROCK-FORMING MINERALS (Physical & Chemical Properties) | EARTH AND LIFE SCIENCE | Science 11 MELC 3

Summary

This educational video introduces the identification of rock-forming minerals through their physical and chemical properties. It clarifies that minerals are naturally occurring, inorganic solids with a crystalline structure and a definite chemical composition, distinguishing them from substances like water and tube ice. The video explores properties such as luster, hardness, color, streak, crystal form, cleavage, fracture, and specific gravity. It also delves into chemical properties and common rock-forming minerals like quartz, feldspar, micas, amphiboles, pyroxene, olivine, and calcite, highlighting their industrial uses and geological significance.

Takeaways

• 💎 Minerals are the fundamental components of rocks and are naturally occurring inorganic solids with an orderly crystalline structure and a definite chemical composition.
• 💧 Water is not considered a mineral because it lacks a solid crystalline structure, and tube ice is not naturally occurring.
• ❄️ A snowflake is an example of a mineral as it possesses all the properties defined for minerals.
• 🔦 Luster refers to the way light is reflected from the surface of a mineral, with metallic and non-metallic types exemplified by pyrite and kaolinite, respectively.
• 💪 Hardness measures a mineral's resistance to being scratched, with a Mohs scale of hardness from 1 (talc) to 10 (diamond).
• 🎨 Color in minerals can vary due to impurities and geological processes, but streak is a more reliable property for identification than color.
• 📐 Crystal form or habit is the natural shape of a mineral before cleavage or fracture, while cleavage is the tendency to break along specific planes of weakness.
• 🌡 Specific gravity is the ratio of a mineral's density to that of water, measured by the amount of water displaced.
• 🧪 Chemical properties of minerals can be tested through various methods, and their classification is based on their chemical compositions.
• 🌐 Silicate minerals, like quartz and feldspar, are the most abundant, making up over 90% of rock-forming minerals.
• 📚 Common rock-forming minerals include quartz, plagioclase feldspar, alkali feldspar, micas, amphiboles, pyroxene, olivine, and calcite, each with specific uses and characteristics.

Q & A

What are the fundamental components of rocks?

Minerals are the fundamental components of rocks. They are naturally occurring, inorganic solids with an orderly crystalline structure and a definite chemical composition.

Is water considered a mineral?

No, water is not considered a mineral because it is not solid and does not have an orderly crystalline structure.

What are the two main types of luster found in minerals?

The two main types of luster are metallic and non-metallic. Examples include metallic luster found in pyrite and non-metallic luster in kaolinite.

What is the Mohs scale of hardness, and what is its range?

The Mohs scale of hardness is a scale that measures the scratch resistance of various minerals, ranging from 1 (softest, like talc) to 10 (hardest, like diamond).

Why is streak considered a more reliable property than color for identifying minerals?

Streak is more reliable than color because it does not vary and is the color of a mineral in powdered form, whereas minerals with the same color may have different colored streaks.

What is the natural shape of a mineral before any cleavage or fracture develops?

The natural shape of a mineral before any cleavage or fracture is known as the crystal form or habit.

What is cleavage, and how does it differ from fracture?

Cleavage is the property of some minerals to break along specific planes of weakness to form smooth, flat surfaces. Minerals that do not exhibit cleavage are said to fracture, which can result in irregular shapes like glass shards, splinters, or fibers.

What is specific gravity, and how is it measured?

Specific gravity is the ratio of the density of a mineral to the density of water, and it is measured based on the amount of water displaced by the mineral.

What is the most stable and least ambiguous basis for the classification of minerals?

The most stable and least ambiguous basis for the classification of minerals is based on their chemical compositions, such as silicates, oxides, sulfates, sulfides, carbonates, native elements, and halides.

What are some common rock-forming minerals mentioned in the script?

Some common rock-forming minerals mentioned are quartz, plagioclase feldspar, alkali feldspar, micas, amphiboles, pyroxene, olivine, and calcite.

What is the raw material for making glass, and which mineral is it derived from?

Silicon dioxide, which is found in quartz, is the raw material used for making glass.

What is the major component of sedimentary rocks such as limestone, and what metamorphic rock is produced from it?

Calcite is the major component of sedimentary rocks like limestone, and when subjected to metamorphism, it produces marble.

Outlines

00:00

📚 Introduction to Mineral Identification

This video script introduces the concept of identifying rock-forming minerals through their physical and chemical properties. It clarifies what constitutes a mineral, emphasizing that minerals are naturally occurring, inorganic solids with a crystalline structure and a definite chemical composition. The script dispels misconceptions about common substances like water, tube ice, and snowflakes, explaining why only snowflakes qualify as minerals. The lesson then delves into the physical properties of minerals, such as luster (reflective properties), hardness (resistance to scratching), color, streak (color in powdered form), crystal form or habit, cleavage, and fracture. It also touches on specific gravity and chemical properties, highlighting the significance of chemical composition in mineral classification, with a focus on groups like silicates, oxides, sulfates, sulfides, carbonates, native elements, and halides.

05:04

💎 Common Rock-Forming Minerals and Their Properties

The second paragraph of the script focuses on the identification and properties of common rock-forming minerals. It begins by discussing the luster of minerals, distinguishing between metallic and non-metallic types, with examples like pyrite and kaolinite. The script then explains hardness, referencing the Mohs scale of mineral hardness, and the importance of streak as a more reliable property than color due to variations in mineral coloration. The description of crystal form or habit, cleavage, and fracture provides insight into the natural shapes and breaking patterns of minerals. The script also covers specific gravity and introduces a variety of common minerals, including quartz, plagioclase feldspar, alkali feldspar, micas, amphiboles, pyroxene, and all divine. It concludes with a brief mention of olivine and calcite, their uses, and the geological transformations they undergo, such as the formation of marble from limestone through metamorphism.

Keywords

💡Mineral

A mineral is defined in the script as a naturally occurring, inorganic solid with an orderly crystalline structure and a definite chemical composition. This definition is central to the video's theme as it distinguishes minerals from other substances like water or ice, which do not possess the same properties. For example, water is not considered a mineral because it lacks a crystalline structure in its liquid state.

💡Luster

Luster refers to the way light is reflected from the surface of a mineral, which is an important physical property used in mineral identification. In the video, two types of luster are mentioned: metallic, as seen in pyrite, and non-metallic, as in kaolinite. Understanding luster helps in distinguishing between different minerals based on their reflective properties.

💡Hardness

Hardness is a measure of a mineral's resistance to being scratched, and it is quantified on the Mohs scale of mineral hardness, ranging from 1 (softest) to 10 (hardest). This concept is integral to the video as it helps in identifying minerals by their relative scratch resistance, with talc being the softest and diamond the hardest. The script uses this property to illustrate the differences between various minerals.

💡Color

Color is a physical property of minerals that can result from impurities or geological processes. While color can be a distinguishing feature, the script notes that it is not always reliable due to variations. For instance, azurite is mentioned as being purple, and sulfur is yellow, but the script emphasizes that streak is a more consistent property for identification.

💡Streak

Streak is the color of a mineral when it is in powdered form, which is a more reliable property for mineral identification than overall color. The script points out that minerals with the same color may have different streaks, using hematite as an example, thus highlighting the importance of streak in distinguishing minerals.

💡Crystal Form or Habit

The natural shape of a mineral before any cleavage or fracture is referred to as its crystal form or habit. This is a key concept in the video as it helps in identifying the mineral's structure. The script does not provide specific examples but explains that this property is distinct from cleavage or fracture.

💡Cleavage

Cleavage is the property of some minerals to break along specific planes of weakness, resulting in smooth, flat surfaces. The script explains that minerals with cleavage are distinct from those that fracture, which break in irregular patterns. This property is important for classifying and identifying minerals.

💡Fracture

Fracture refers to how a mineral breaks when not exhibiting cleavage. The script describes different types of fractures, such as conchoidal (like glass), uneven, or splintery, which are important for understanding a mineral's physical characteristics and its behavior when broken.

💡Specific Gravity

Specific gravity is the ratio of the density of a mineral to the density of water, and it is measured by the amount of water displaced by the mineral. This property is used to differentiate minerals in the video, as it provides insight into their relative densities.

💡Chemical Composition

The chemical composition of a mineral is a fundamental aspect of its identity and is the basis for classifying minerals. The script emphasizes that the most stable and least ambiguous way to classify minerals is by their chemical compositions, such as silicates, oxides, sulfates, sulfides, carbonates, native elements, and halides.

💡Rock-Forming Minerals

Rock-forming minerals are those that are the fundamental components of rocks. The video discusses several common rock-forming minerals, such as quartz, feldspar, micas, amphiboles, pyroxene, olivine, and calcite, each with specific properties and uses, illustrating the diversity and importance of these minerals in geology.

Highlights

Video discusses identifying rock-forming minerals using their physical and chemical properties.

Learning competency focuses on identifying common rock-forming minerals.

Minerals are inorganic solids with a crystalline structure and definite chemical composition.

Water is not considered a mineral as it lacks a solid crystalline structure.

Tube ice is not a mineral due to its non-naturally occurring nature.

Snowflakes are considered minerals as they meet the mineral definition criteria.

Luster is the reflection of light from a mineral's surface, with metallic and non-metallic types.

Hardness measures a mineral's resistance to scratch, on a scale from 1 to 10.

Color in powdered form (streak) is a more reliable property than color for mineral identification.

Crystal form or habit refers to the natural shape of a mineral before cleavage or fracture.

Cleavage is the property of minerals to break along specific planes, forming smooth surfaces.

Specific gravity is the ratio of a mineral's density to water's density.

Chemical tests, such as taste and reaction, are used for mineral classification.

Mineral classification is primarily based on their chemical compositions.

Silicates are minerals containing silicon and oxygen, making up over 90% of rock-forming minerals.

Quartz, made of silicon dioxide, is used as a raw material for making glass.

Plagioclase feldspar is an important industrial mineral used in ceramics.

Alkali feldspar, commonly pink to white, is used as a raw material for porcelain.

Micas are silicate minerals common in intrusive igneous rocks and sedimentary rocks.

Amphiboles are silicate minerals found in many igneous and metamorphic rocks.

Pyroxene crystals are commonly faceted as gemstones, such as precious chain.

Olivine is a silicate mineral, transparent and commonly faceted as gemstones.

Calcite is the major component of sedimentary rocks like limestone and metamorphic marble.

Transcripts

hello grade 11.

in this video you will learn about

identifying wrap forming minerals

using their physical and chemical

properties

[Music]

our discussion will focus on the

learning competency

identify common rock-forming minerals

using their physical

and chemical properties

do you consider water as a mineral

how about tube ice or snowflakes are

these minerals

minerals are the fundamental components

of rocks

they are naturally occurring

inorganic solid with an orderly

crystalline structure

in a definite chemical composition

[Music]

therefore water is not a mineral because

it is not solid

in crystalline tube ice is also not a

mineral because it is not naturally

occurring

but a snowflake possesses all the

properties under the definition

of a mineral now let's discuss the

physical and chemical properties of rock

forming minerals

let's start with luster this refers to

the way

light is reflected from the surface of a

mineral

types of luster we have the metallic and

the non-metallic

examples are metallic cluster pyrite and

non-metallic plaster kaolinite

next is hardness it is a measure of the

resistance of a mineral to scratch

the most scale of hardness measures the

scratch resistance of various minerals

from a scale of one to ten

with dark as the softest and diamond as

the hardest mineral

this was designed by mineralogist

friedrich moss

next is color minerals display a variety

of colors

resulting from impurities and also from

geologic processes like

weathering examples

of coloring azerite is purple

sulfur is yellow we also have

strict minerals color in powdered form

streak is a more reliable property than

color because street does not vary

minerals that have the same color may

have different colored strip

example is this one the hematite next

is the crystal form or habit it is the

natural shape of the mineral before the

development of

any cleavage or fracture

we also have cleavage the property of

some minerals to break along specific

planes of weakness to form smooth

flat surfaces minerals that do not

exhibit cleavage

are said to fracture when broken some

break leg glass some into splinters

or fibers last is the specific gravity

which is the ratio of the density of the

mineral and the density of water

measured based on the amount of water

displaced

to determine chemical properties sample

chemical test

is done for example order

taste and reaction to assay

the most stable and least ambiguous

basis for classification of minerals is

based on their chemical compositions

silicate for example is a mineral

containing the two most abundant

elements in the earth's crust

namely silicon and oxygen over 90

percent of rock forming minerals belong

to this group

we also have oxides sulfates sulfides

carbonates the native elements and

the halites

now let's talk about the common wrap

forming minerals

first we have quartz quartz is usually

called silica

it is made up of silicon dioxide which

is the raw material for making glass

next we have plagioclase feldspar

which is an important industrial mineral

used in ceramics

next we have alkali feldspar it is

commonly pink to white used as a raw

material to make porcelain

we also have micas micas are family of

silicate minerals

they are common materials in intrusive

igneous rocks

and also found in sedimentary we also

have the amphiboles

are a family of silicate minerals they

are a component of many igneous and

metamorphic

we also have pyroxene these crystals

are commonly faceted as gemstones for

instance precious chain

is a pyroxene next is all divine

a silicate mineral clear and transparent

olivine crystals are commonly faceted

as gemstones last is calcite

calcite is the major component of

calculus sedimentary rocks such as

limestone

metamorphism produces marble

and that's it now let's check your

understanding

direction identify the properties of

rock-forming minerals described in the

following

one refers to the way light is reflected

from the surface of a mineral

answer

that's correct luster two

minerals color in powdered form

answer

very good strict number three

it is a measure of the resistance of a

mineral to scratch

there you have it hardness

and that's the end of our lesson

congratulations

[Music]

you