1. Ответьте на следующие вопросы по тексту:

How can complete identification of many minerals be made?

1. What feature of a mineral catches the eye first?

2. What colour can minerals be?

3. What is luster?

4. What terms are used to describe luster?

5. What does the term ‘transparent’ mean?

6. What does the term ‘translucent’ mean?

7. What does the term ‘opaque’ mean?

8. What does the term ‘structure’ mean?

9. What is cleavage?

10. What cleavage may minerals possess?

11. How can knowing the cleavage angle be of help?

12. What terms are used to describe the ease of cleavage? What do they mean?

2. Найдите в тексте предложения, содержащие словосочетания из комментариев и переведите их письменно. Составьте свои предложения с этими словосочетаниями.

3. В тексте Colour, Luster, Transparency and Cleavage подчеркнуты атрибутивные обороты. Переведите предложения с этими оборотами. Помните, что перевод таких предложений чаще всего начинается с последнего слова.

4. Найдите в тексте информацию по следующим вопросам:

1. What are the main physical properties of the minerals?

2. What does the colour of the minerals depend on?

3. How is luster called if it’s difficult to determine it for sure?

4. What is the difference between transparent, translucent and opaque minerals?

5. What can the knowledge of mineral cleavage help in?

TEXT 2.4.

VOCABULARY WORK:

• Запомните следующие слова:

Научный вокабуляр:

carbonate ['kRbq‚neIt] - карбонат, углекислая соль

silicate ['sIlI‚keIt] - силикат; соль кремневой кислоты

ester ['estq] - сложный эфир

tetrahedron [‚tetrq'hJdrqn] - тетраэдр, четырёхгранник

oxygen ['OksIGqn] - кислород

sulphur ['sAlfq] - сера

phosphorus ['fOsfqrqs] - фосфор

magnesium [mxg'nJzIqm] - магний

calcium ['kxlsIqm] - кальций

manganese ['mxNgq‚nJz] - марганец

barium ['beqrIqm] - барий

chromium ['krqumIqm] - хром

nickel ['nIkl] - никель

silver ['sIlvq] - серебро

zinc [zINk] - цинк

tin [tIn] - олово

lead [led] - свинец

antimony ['xntImqnI] - сурьма

gold [gquld] - золото

Общеязыковой вокабуляр:

save [seIv] for - за исключением, кроме

confirm [kqn'fE:m] - подтверждать, подкреплять

focus ['fqukqs] - сосредоточиваться

distribution [‚dIstrI'bjHSn] - распределение

rare [req] - редкий

abundant [q'bAndqnt] - богатый

scatter ['skxtq] - посыпать, разбрасывать

• Прочтите следующий текст и переведите его:

Minerals Useful to People

Mineral is any of a class of naturally occurring solid inorganic substances with a characteristic crystalline form and a homogeneous chemical composition. All minerals can be divided into the ores and the rock-forming minerals. Ore is any naturally occurring mineral or aggregate of minerals from which economically important constituents, especially metals, can be extracted. In their turn the rock-forming minerals can be divided into three groups: the essential minerals which make up the bulk of the rocks, the accessory minerals, which are present only in small quantities, and the secondary minerals which are derived from the breakdown of other minerals.

Save for the carbonates and quartz the essential minerals are all silicates. Silicate is a salt or ester of silicic acid, especially one of a large number of usually insoluble salts with polymeric negative ions having a structure formed of tetrahedrons of SiO4 groups linked in rings, chains, sheets, or three dimensional frameworks. Silicates constitute a large proportion of the earth’s minerals and are present in cement and glass. Silicates are classified in keeping with their properties into groups. The basis for this grouping has been confirmed by their atomic structure research by the X-ray analysis methods.

The science of geology also focuses on the study of all the elements distribution. The second most common of all the elements (after oxygen) is silicon, which in its sand form has great economic value. It also occurs in quartz, granite, feldspar and clay. The next most common elements are aluminium, iron, sulphur, phosphorus, calcium, magnesium, manganese, barium, chromium, nickel, etc.

The relatively rarer metals - silver, zinс, tin, lead, antimony, gold, and others, - can be found in small quantities practically everywhere in the earth’s crust. The rarer elements are also scattered through the rocks, and occur in more or less abundant minerals.

Комментарии к тексту:

economically [‚Jkq'nOmIklI] important [Im'pLtnt] constituents [kqn'stItjuqnts] - экономически важные составляющие

rock-forming [‚rOk'fLmIN] minerals - породообразующие полезные ископаемые

essential [I'senSl] minerals - основные минералы

the bulk [bAlk] of the rocks - основная масса горных пород

accessory [qk'sesqrI] mineral - минерал-спутник; тяжёлый минерал

secondary ['sekqndqrI] mineral - вторичный минерал

silicic [sI'lIsIk] acid ['xsId] - кремниевая кислота

insoluble [In'sOljubl] salts - нерастворимые соли

polymeric [‚pOlI'merIk] negative ['negqtIv] - ions полимерные отрицательные ионы

linked [lINkt] in rings [rINz], chains [CeInz], sheets [SJts] - соединены в форме колец, цепей, пластов

three-dimensional [‚TrJdaI'menSnl] frameworks ['freImwE:k] - трехмерные структуры

in keeping ['kJpIN] with - согласовываться с чем-л., соответствовать чему-л.

the X-ray ['eks‚reI] analysis [q'nxlqsIs] methods ['meTqdz] - метод рентгеноструктурного анализа

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