Eduqas GCSE Geology · 1.1

Minerals

50 revision questions with answers for 1.1 Minerals in Eduqas GCSE Geology (spec C480QS). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, Five Degrees, Associations, or read every question and answer below.

All 50 questions and answers

Question 1
What is a mineral?
Answer:
A naturally occurring inorganic solid with an ordered crystal structure and a characteristic chemical composition or range of compositions.
Question 2
How do quartz crystals form in granite?
Answer:
They crystallise as molten magma cools and solidifies.
Question 3
Name two minerals that can crystallise from a melt.
Answer:
Feldspar and mica; quartz, olivine and augite are also examples.
Question 4
How can garnet develop during metamorphism?
Answer:
Minerals in a pre-existing rock recrystallise as temperature or pressure increases.
Question 5
How can halite crystallise from seawater?
Answer:
Evaporation concentrates dissolved substances until halite precipitates.
Question 6
How can quartz or calcite act as a sedimentary cement?
Answer:
Dissolved material in pore water crystallises in spaces between sediment grains, binding them.
Question 7
What is a hydrothermal mineral deposit?
Answer:
Minerals deposited from hot, mineral-rich fluids, commonly in fractures or faults.
Question 8
Why can quartz occur as a gangue mineral in a vein?
Answer:
It crystallises from hydrothermal fluids but is not the valuable ore mineral being extracted.
Question 9
Distinguish an ore mineral from gangue.
Answer:
An ore mineral contains a useful material recoverable economically; gangue is the unwanted material associated with it.
Question 10
Name the lead ore mineral on the specification.
Answer:
Galena is a lead ore mineral.
Question 11
Name an iron ore mineral on the specification.
Answer:
Haematite is an iron ore mineral.
Question 12
A fault contains galena and quartz. Which is the ore and which is the gangue?
Answer:
Galena is the lead ore; quartz is gangue in this deposit.
Question 13
Put these stages in order: vein crystallises; fracture forms; hot mineral-rich fluid enters.
Answer:
Fracture forms; hot fluid enters; minerals crystallise as conditions change.
Question 14
Why is colour alone often unreliable for identifying a mineral?
Answer:
A single mineral can occur in different colours, and different minerals can share a colour.
Question 15
What is mineral streak?
Answer:
The colour of a mineral's powdered form, found by rubbing it on unglazed porcelain.
Question 16
Why might streak be more useful than surface colour?
Answer:
The powder colour may be more consistent than a weathered or variably coloured surface.
Question 17
What is lustre?
Answer:
The way a mineral surface reflects light, for example metallic or non-metallic.
Question 18
What does a metallic lustre look like?
Answer:
It reflects light like a metal, rather than like glass or a dull surface.
Question 19
What is cleavage in a mineral?
Answer:
A tendency to break along repeated flat planes of weakness in its crystal structure.
Question 20
How is fracture different from cleavage?
Answer:
Fracture is breakage along irregular surfaces; cleavage follows preferred planes.
Question 21
What is hardness?
Answer:
Resistance of a mineral surface to being scratched.
Question 22
How can you compare the hardness of two minerals?
Answer:
Try to scratch each with the other; the mineral that scratches the other is harder.
Question 23
If mineral A scratches mineral B but B cannot scratch A, which is harder?
Answer:
A is harder than B.
Question 24
A mineral scratches glass but is scratched by quartz. What can you infer?
Answer:
It is harder than glass and softer than quartz, within the limitations of the tests.
Question 25
Why should a scratch be checked with a fingertip or hand lens?
Answer:
A powder mark can be mistaken for a genuine groove in the mineral surface.
Question 26
How can calcite be distinguished from quartz using dilute hydrochloric acid?
Answer:
Calcite effervesces with the specified dilute acid; quartz does not.
Question 27
What visible result shows that calcite reacts with dilute hydrochloric acid?
Answer:
Effervescence: bubbles of carbon dioxide form on the mineral.
Question 28
What concentration of hydrochloric acid does this specification name for mineral tests?
Answer:
0.5 mol dm^-3 hydrochloric acid.
Question 29
Give one safety step when testing a mineral with dilute acid.
Answer:
Wear eye protection and use only a small drop under supervision.
Question 30
A mineral is soft, metallic and leaves a grey streak. Which listed ore might it be?
Answer:
Galena is a likely identification; check the full set of properties against the data sheet.
Question 31
A sample gives a red-brown streak and has a metallic to earthy appearance. Which ore is likely?
Answer:
Haematite; use additional properties and the data sheet to confirm.
Question 32
A sample fizzes in dilute acid and has cleavage. Which listed mineral is likely?
Answer:
Calcite; compare its remaining properties with the data sheet.
Question 33
A pale mineral has no cleavage and does not fizz. Suggest a listed mineral.
Answer:
Quartz is a possibility; hardness and other observations should be checked.
Question 34
Why use several mineral tests instead of a single observation?
Answer:
A combination of independent properties narrows down similar-looking minerals more reliably.
Question 35
How is the cleavage of mica commonly recognised?
Answer:
It separates into thin, flexible sheets along one excellent cleavage direction.
Question 36
How would you check whether an apparent crystal face is cleavage?
Answer:
Look for repeated parallel flat breakage surfaces and compare with the mineral's known properties.
Question 37
What should you record before using a mineral-identification key?
Answer:
Observations such as colour, lustre, streak, hardness, cleavage and acid reaction.
Question 38
A mineral leaves a mark on a streak plate but no groove. What has been tested?
Answer:
The streak, not necessarily its hardness against the plate.
Question 39
Why might weathered surfaces mislead a mineral identification?
Answer:
Weathering can alter surface colour or lustre, so inspect a fresh surface when safe.
Question 40
A mineral occurs as tiny crystals in a rock. What tool helps you observe them?
Answer:
A hand lens; a microscope or photomicrograph can show still smaller features.
Question 41
What can a scanning electron microscope reveal about a mineral sample?
Answer:
It can produce detailed images of very small-scale features and textures.
Question 42
What can an electron microprobe determine about a mineral?
Answer:
Its chemical composition at a small scale.
Question 43
Why is a microprobe helpful when two minerals look similar?
Answer:
Their chemical compositions can differ even when visible appearance is similar.
Question 44
Does the specification require students to use an electron microprobe?
Answer:
No. Students should know what such techniques can do; access is not required.
Question 45
A vein cuts a sandstone and contains calcite. Give a likely sequence.
Answer:
Sandstone formed, a fracture opened, and mineral-rich fluid deposited calcite in it.
Question 46
Why is a mineral vein usually younger than the rock it cuts?
Answer:
The host rock had to exist before the fracture and vein could cut it.
Question 47
How could calcite form in both marble and a sedimentary rock?
Answer:
It can recrystallise during metamorphism and also precipitate as cement from pore water.
Question 48
Are quartz and calcite limited to one mode of formation?
Answer:
No. Each can form in several settings; their surrounding rock and textures help identify the process.
Question 49
A deposit weighs 200 tonnes and contains 8 tonnes of ore. What percentage is ore?
Answer:
8 / 200 x 100 = 4%.
Question 50
Why is a geological context useful when identifying a mineral?
Answer:
Its location, associated minerals and mode of formation provide evidence to check against physical tests.

1.2 Igneous Rocks and Processes →

Minerals

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