Test yourself

Task: Tell whether the sentences are true or false. Correct the false ones.

1. As early as 3700 BC, Egyptians began mining salt, silver, and quartz.

2. The discovery of gold marked the decline of the Bronze Age.

3. During the Middle Ages, mining of a variety of minerals was common throughout Europe.

4. We talk about minerals when we mean health and fitness.

5. Synthetic materials are also are considered minerals.

6. Minerals are solid substances, which means their atoms are arranged in an orderly, repetitive manner.

7. Most minerals have a nonmetallic luster and are called glassy.

8. When shells and coral reefs are buried and become part of the rock record, they are considered minerals by geologists.

9. Copper and galena exhibit a submetallic luster.

10. Streak can help distinguish between minerals with metallic luster and those with nonmetallic luster.

Unit 12 mineralogy Part 2

Task 1. Read and memorize the following words:

determine by - визначатися	chemical bond – хімічний зв’язок
bend - гнутися	snap – приходити у потрібний стан
brittle – крихкий, ламкий	shatter – розбити вщент, розколоти
cleavage – кліваж, шаруватість	fracture - руйнування
irregular – неправильний, несиметричний, нерівний	mica - слюда
malleable – м’який	hammer - бити молотом
plane – площина, паралельна кліважу	smooth – гладкий, з рівною поверхнею
release – послабити, звільнити	abrasion – стирання, зношування, шліфування
resistance - опір	fluorite – плавиковий шпат
scratching – дряпання, шкрябання	rub - терти
stress – тиск,напруга	toughness – міцність, твердість
tenacity – міцність, сила зчеплення, опір розриву	hardness - твердість
uneven - нерівний

Task 2. Transcribe and translate the following words: gypsum, ionically, micas, cleavage, tenacity, talc.

Task 3. Read the following text, translate it into Ukrainian. Pay special attention to the pronunciation of the following words: fracture, tenacity, malleable, elastic, diagnostic, sectile, original, numerical, identified.

Mineral Strength

How easily minerals break or deform under stress is determined by the type and strength of the chemical bonds that hold the crystals together. Mineralogists use terms including tenacity, hardness, cleavage, and fracture to describe mineral strength and how minerals break when stress is applied.

TENACITY. The term tenacity describes a mineral’s toughness, or its resistance to breaking or deforming. Minerals that are ionically bonded, such as fluorite and halite, tend to be brittle and shatter into small pieces when struck. By contrast, minerals with metallic bonds, such as native copper, are malleable, or easily hammered into different shapes. Minerals, including gypsum and talc, that can be cut into thin shavings are described as sectile. Still others, notably the micas, are elastic and will bend and snap back to their original shape after the stress is released.

HARDNESS. One of the most useful diagnostic properties is hardness, a measure of the resistance of a mineral to abrasion or scratching. This property is determined by rubbing a mineral of unknown hardness against one of known hardness, or vice versa. A numerical value of hardness can be obtained by using the Mohs scale of hardness, which consists of 10 minerals arranged in order from 1 (softest) to 10 (hardest). It should be noted that the Mohs scale is a relative ranking, and it does not imply that mineral number 2, gypsum, is twice as hard as mineral 1, talc. In fact, gypsum is only slightly harder than talc, as FIGURE 12.1 B indicates.

CLEAVAGE. In the crystal structure of many minerals, some atomic bonds are weaker than others. It is along these weak bonds that minerals tend to break when they are stressed. Cleavage is the tendency of a mineral to break (cleave) along planes of weak bonding. Not all minerals have cleavage, but those that do can be identified by the relatively smooth, flat surfaces that are produced when the mineral is broken. Do not confuse cleavage with crystal shape. When a mineral exhibits cleavage, it will break into pieces that all have the same geometry.

FRACTURE. Minerals having chemical bonds that are equally, or nearly equally, strong in all directions exhibit a property called fracture. When minerals fracture, most produce uneven surfaces and are described as exhibiting irregular fracture.

Task 4. Answer the following questions, using the vocabulary from Task 1.

1. What is determined by the type and strength of the chemical bonds?

2. What does the term tenacity describe?

3. When do we call minerals brittle? Malleable? Sectile? Elastic?

4. What diagnostic property is considered to be one of the most useful?

5. What is hardness?

6. How can a numerical value of hardness be obtained?

7. What is cleavage?

8. Do all minerals have cleavage?

9. What is the difference between cleavage and crystal shape?

10. What property do minerals having chemical bonds that are equally, or nearly equally, strong in all directions exhibit?

Task 5. Complete the following sentences from the text in Task 3.

1. The term … describes a mineral’s toughness.

2. The term … describes a measure of the resistance of a mineral to abrasion or scratching.

3. … is the tendency of a mineral to break (cleave) along planes of weak bonding.

4. When minerals fracture, most produce uneven surfaces and are described as exhibiting … .

5. Minerals that are … tend to be brittle and shatter into small pieces when struck.

6. Minerals with … are malleable, or easily hammered into different shapes.

Task 6. Find English equivalents for the following (see the text).

Щоб описати міцність мінералів; як ламаються мінерали; твердість мінералів; розколотись на маленькі шматочки; навпаки; легко розбити молотком на шматки різної форми; порізати на тонку стружку; мінерали, що розташовані по порядку – від найм’якіших до найтвердіших; зв’язки між атомами; ламатися під дією зовнішніх сил; відносно гладка, плоска поверхня; плутати кліваж з кристалічною формою; розламатися на шматки однакової форми; нерівна поверхня.

Task 7. Build up 6 simple sentences using the English vocabulary from Task 6. All the verbs must be used in the Passive voice.

Task 8. Give a short summary of the text from Task 3.

Task 9. Look at Figure 12.1. It shows hardness scales. Figure A represents Mohs scale of hardness, with the hardness of some common objects. Figure B shows relationship between Mohs relative hardness scale and an absolute hardness scale. Compare hardness of the following minerals and common objects:

• gypsum and wire nail;

• apatite and fingernail;

• calcite and glass and knife blade.

Task 10. Talk about tenacity, hardness, cleavage and fracture as the most important characteristics of mineral strength.