Rocks and Minerals by UTH Rocks and Minerals by UTH    

Lesson 13: Physical Properties: Fluorescence

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. The final studied physical property of rocks and minerals is fluorescence. Fluorescence is the emission of light by a material when stimulated by ultraviolet light, visible light, X-rays or other radiation.

Vocabulary

Physical Property: Characteristics of matter not involving a change in chemical composition.
Fluorescence: The emission of light by a material when stimulated by ultraviolet light, visible light, X-rays or other radiation.
Radiation: The process of emitting energy via waves or particles, such as the sun emitting light, heat, and ultraviolet radiation.
Gemstone: A precious stone, usually of substantial monetary value or prized for its beauty or shine, usually made of minerals.
Birthstone: Any of twelve gemstones traditionally associated with the month of one's birth.

Rock or Mineral of the Week

• Rubies, which are a type of corundum gemstone colored with chromium (Cr), range from pink to a deep red color.
• Rubies were named for the Latin word for red - ruber.
• Rubies are prized in part, due to their hardness. They are almost as hard as diamonds, coming in at 9.0 on the Mohs scale.
• As with diamonds, the color, cut, clarity, and size determine the monetary value of a ruby.
• Rubies emit light or fluoresce under UV light and green light.

Physical Characteristics

• Color: Pink to red
• Hardness: 9
• Luster: Subadamantine, vitreous
• Cleavage: None
• Streak: White
• Tenacity: Brittle

Location

• All over the world including Thailand, Nepal, Taiwan, Vietnam, Afghanistan, Pakistan, and Namibia

Interesting Facts

• Sapphires are also made out of corundum, but colored with other elements such as iron (Fe) and titanium (Ti).

• The ruby is the birthstone for those born in July.

• The most valuable color of the ruby is called pigeon's blood.
• The most valuable ruby in the world is the Sunrise Ruby, originally mined in Myanmar.

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:

• Aluminum (Al)
• Chromium (Cr)
• Oxygen (O)
• In which group and period is chromium (Cr)?

Activity 3: Map the Lesson

• Rubies are found all over the world including the countries of Thailand, Nepal, Taiwan, Vietnam, Pakistan (Pak.), and India.
• Find these countries on the map of Asia.

Activity 4: 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 5: 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 fluorescence a physical property or a chemical property?

1 / 5

Answer 1

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

1 / 5

Question 2

Describe something about rubies (Al2O3 + Cr).

2 / 5

Answer 2

Rubies are made from chromium-tinted corundum. They range from pink to red in color and can be highly valuable.

2 / 5

Question 3

Is a ruby (Al2O3 + Cr) a compound?

3 / 5

Answer 3

Yes, a ruby (Al2O3 + Cr) is a compound consisting of more than one type of element.

3 / 5

Question 4

How many different elements do rubies (Al2O3 + Cr) contain?

4 / 5

Answer 4

Rubies (Al2O3 + Cr) contain three types of elements - aluminum (Al) and oxygen (O) plus trace amounts of chromium (Cr).

4 / 5

Question 5

What gives rubies their beautiful red color?

5 / 5

Answer 5

Trace amounts of chromium (Cr) give rubies their beautiful red color.

5 / 5

❮ ❯

1. Is fluorescence a physical property or a chemical property? Fluorescence is a physical property, for it does not involve a change in chemical composition.
2. Describe something about rubies (Al2O3 + Cr). Rubies are made from chromium-tinted corundum. They range from pink to red in color and can be highly valuable.
3. Is a ruby (Al2O3 + Cr) a compound? Yes, a ruby (Al2O3 + Cr) is a compound consisting of more than one type of element.
4. How many different elements do rubies (Al2O3 + Cr) contain? Rubies (Al2O3 + Cr) contain three types of elements - aluminum (Al) and oxygen (O) plus trace amounts of chromium (Cr).
5. What gives rubies their beautiful red color? Trace amounts of chromium (Cr) give rubies their beautiful red color.

References

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

'Sunrise Ruby.' Wikipedia. en.wikipedia.org/wiki/Sunrise_Ruby. n.p.

'File:Sunrise Ruby.jpg.' License: Fair Use. Wikipedia. en.wikipedia.org/wiki/File:Sunrise_Ruby.jpg. n.p.

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