Rocks and Minerals by UTH Rocks and Minerals by UTH    

Lesson 9: Physical Properties: Cleavage

Directions

Study the lesson for one week.

Over the week:

• Read the lesson.
• Review the synopsis.
• Recite aloud the vocabulary words and their definitions.
• Study the rock and mineral of the week.
• Complete the enrichment activities.
• Study the review questions.

Synopsis

Rocks and minerals may be identified by one or more of their physical properties. One identifying physical property of rocks and minerals is cleavage. Cleavage is the tendency of a mineral to split cleanly along flat, smooth surfaces or plains.

Vocabulary

Physical Property: Characteristics of matter not involving a change in chemical composition.
Cleavage: The tendency of a mineral to split cleanly along flat, smooth surfaces or plains.
Transparent: See-through, clear; having the property that light passes through it almost undisturbed.
Translucent: Allowing light to pass through, but diffusing it.

Rock or Mineral of the Week

Overview

• Muscovite, a type of mica, is an example of a mineral showing perfect cleavage.
• The thin layers of mica tend to be transparent or translucent, allowing light to pass through.

Physical Characteristics

• Color: Black, brown, silver - but when split, sheets may be colorless or tinted with brown, yellow, green, or pink
• Hardness: 2.5 to 3
• Luster: Pearly to vitreous
• Cleavage: Perfect
• Streak: White, shedding flakes of material
• Tenacity: Sectile

Locations

• Many places all over the world

Interesting Facts

• Muscovite can often be peeled into thin layers using only your hands.
• Enormous sheets of muscovite - greater than 10 feet by 10 feet, have been found in India.
• See the window panes made of sheets of muscovite.

Enrichment

Activity 1: Narrate the Lesson

• After reading or listening to the lesson, narrate the lesson aloud using your own words.

Activity 2: Can You Find It?

Find the following elements on the periodic table:

• Potassium (K)
• Aluminum (Al)
• Silicon (Si)
• Oxygen (O)
• Hydrogen (H)
• In which group and period is Hydrogen (H)?

Activity 3: Take a Nature Walk

• Embark on a nature walk.
• Collect one rock or mineral specimen.
• Use the gathered specimen to create the field book entry.

Activity 4: Complete a Field Book Entry   

After your nature walk, complete page 6 in 'Fifth Grade Science Rocks and Minerals Notebook Pages.'

Review

Question 1

Is cleavage a physical property or a chemical property?

1 / 4

Answer 1

Cleavage is a physical property, for it does not involve a change in chemical composition.

1 / 4

Question 2

Describe something about muscovite (KAl2(Si3AlO10)(OH)2).

2 / 4

Answer 2

Muscovite is a black, brown, or silver mineral with perfect cleavage.

2 / 4

Question 3

Is muscovite (KAl2(Si3AlO10)(OH)2) a compound?

3 / 4

Answer 3

Yes, muscovite (KAl2(Si3AlO10)(OH)2) is a compound containing more than one type of element.

3 / 4

Question 4

How many different elements does muscovite (KAl2(Si3AlO10)(OH)2) contain?

4 / 4

Answer 4

Muscovite (KAl2(Si3AlO10)(OH)2) contains five types of elements - Potassium (K), Aluminum (Al), Silicon (Si), Oxygen (O), and Hydrogen (H).

4 / 4

❮ ❯

1. Is cleavage a physical property or a chemical property? Cleavage is a physical property, for it does not involve a change in chemical composition.
2. Describe something about muscovite (KAl2(Si3AlO10)(OH)2). Muscovite is a black, brown, or silver mineral with perfect cleavage.
3. Is muscovite (KAl2(Si3AlO10)(OH)2) a compound? Yes, muscovite (KAl2(Si3AlO10)(OH)2) is a compound containing more than one type of element.
4. How many different elements does muscovite (KAl2(Si3AlO10)(OH)2) contain? Muscovite (KAl2(Si3AlO10)(OH)2) contains five types of elements - Potassium (K), Aluminum (Al), Silicon (Si), Oxygen (O), and Hydrogen (H).

References

'Cleavage (crystal).' Wikipedia. en.wikipedia.org/wiki/Cleavage_(crystal). n.p.

'Muscovite.' Wikipedia. en.wikipedia.org/wiki/Muscovite. n.p.

Cited Physical Properties. Geology.com. geology.com/rocks. n.p.