4B2 Earth's Minerals and Rocks

Question 1

Define:

Mineral

Answer 1

A natural, inorganic solid with a set composition and crystal structure.

Minerals form through geological processes and are the building blocks of rocks. Examples include quartz, feldspar, and mica.

Question 2

What is the most abundant mineral in Earth’s crust?

Answer 2

Feldspar

Feldspar is the most abundant mineral group in Earth’s crust, making up over 50% and potentially as much as 60% depending on geological studies.

Question 3

True or False:

Rocks are made of one or more minerals.

Answer 3

True

Rocks are aggregates of minerals and may also contain organic material. For example, granite is composed of quartz, feldspar, and mica.

Question 4

What property measures a mineral’s resistance to scratching?

Answer 4

Hardness

Hardness is determined using the Mohs scale, which ranges from 1 (talc) to 10 (diamond). It helps identify minerals by testing their ability to resist scratches from objects or other minerals.

Question 5

What property describes the way a mineral reflects light?

Answer 5

Luster

Luster can be metallic (shiny like metal) or non-metallic (e.g., glassy, pearly, or dull).

Question 6

True or False:

Streak is the color of a mineral in powdered form.

Answer 6

True

Streak is tested by rubbing a mineral on a streak plate (unglazed porcelain). It often reveals a consistent color, unlike the surface color, which may vary.

Question 7

What property involves the way a mineral breaks along flat planes?

Answer 7

Cleavage

Cleavage occurs when minerals break along specific planes of weakness. The number and quality of cleavage planes vary by mineral type.

Question 8

What refers to a mineral’s mass per unit volume?

Answer 8

Density

Density, also called specific gravity, is calculated as mass divided by volume. Higher densities usually indicate the presence of heavy elements like lead or iron.

Question 9

Fill in the blank:

Minerals with no defined cleavage exhibit ________.

Answer 9

fracture

Fracture describes irregular breaks in minerals. Examples include conchoidal (shell-like) fracture in quartz and splintery fracture in asbestos.

Question 10

True or False:

All minerals are inorganic.

Answer 10

True

By definition, minerals are naturally occurring, inorganic substances with a definite chemical composition and crystalline structure.

Question 11

What type of cleavage does calcite exhibit?

Answer 11

Rhombohedral

Calcite breaks into rhombohedron-shaped fragments due to its three planes of cleavage not intersecting at right angles.

Question 12

What property describes the ability of a mineral to transmit light?

Answer 12

Transparency

Minerals can be transparent (clear, light passes through), translucent (light diffuses), or opaque (no light passes through).

Question 13

What scale is used to measure mineral hardness?

Answer 13

Mohs scale

The Mohs scale ranks minerals from 1 (softest) to 10 (hardest). Common materials like a fingernail (~2.5) or glass (~5.5) are used for comparison.

Question 14

Fill in the blank:

A mineral’s ______ ______ is its natural shape when formed under ideal conditions.

Answer 14

crystal habit

Crystal habit describes a mineral’s external shape, such as prismatic (quartz) or cubic (pyrite), reflecting its internal atomic arrangement.

Question 15

What mineral property causes magnetite to attract a magnet?

Answer 15

Magnetism

Magnetite, a common magnetic mineral, is strongly attracted to magnets, making it easily identifiable.

Question 16

True or False:

Fluorescence is a property where minerals glow under ultraviolet light.

Answer 16

True

Fluorescent minerals like fluorite emit visible light when exposed to UV radiation due to their specific chemical composition.

Question 17

What is the main cause of mineral color?

Answer 17

Elemental composition

Mineral color depends on its chemical elements and impurities. For example, pure quartz is clear, while trace elements like iron can make it pink (rose quartz).

Question 18

What mineral is commonly used to test for a hardness of 3?

Answer 18

Calcite

Calcite can be scratched with a copper coin, making it an ideal reference for Mohs hardness of 3.

Question 19

What mineral is the hardest on the Mohs scale?

Answer 19

Diamond

Diamond is rated 10 on the Mohs scale due to its strong covalent bonds in a tetrahedral crystal structure.

Question 20

Fill in the blank:

Hematite leaves a ____ streak despite appearing metallic gray.

Answer 20

red

Hematite’s reddish streak is a reliable identifier, contrasting its metallic surface appearance.

Question 21

What mineral is known for its perfect cubic cleavage?

Answer 21

Halite

Halite (rock salt) breaks along three perpendicular planes, forming perfect cubes.

Question 22

What mineral has a pearly luster and cleaves into thin sheets?

Answer 22

Mica

Mica minerals, like muscovite and biotite, exhibit sheet-like cleavage due to their layered atomic structure.

Question 23

Which mineral fizzes in acid and is often found in sedimentary rocks?

Answer 23

Calcite

Calcite reacts with dilute acid, releasing carbon dioxide. It is a common mineral in limestone and marble.

Question 24

True or False:

Graphite and diamond are made of the same element.

Answer 24

True

Both graphite and diamond are forms of carbon. Their differing properties result from variations in atomic bonding and structure.

Question 25

# Fill in the blank: Minerals that **break** into rough, uneven surfaces exhibit \_\_\_\_\_\_\_\_.

Answer 25

fracture ## Footnote **Fracture** occurs when minerals lack planes of weakness. Quartz is a common example with conchoidal (curved) fractures.

Question 26

What property makes **gold** ideal for jewelry?

Answer 26

Malleability ## Footnote Gold’s malleability allows it to be **shaped** into thin sheets or intricate designs without breaking.

Question 27

What is the **lightest** mineral in terms of density?

Answer 27

Graphite ## Footnote **Graphite** is light and has a low density due to its layered structure with weak interlayer bonds.

Question 28

# True or False: Quartz has **no** cleavage.

Answer 28

True ## Footnote Quartz fractures rather than cleaves due to its strong atomic bonds in all directions, producing **conchoidal** (shell-like) surfaces.

Question 29

What is the **rock cycle**?

Answer 29

A continuous process that **transforms** rocks through geological processes. ## Footnote The rock cycle shows how rocks are recycled over time due to processes like weathering, melting, and cooling.

Question 30

What are the three main **types** of rocks?

Answer 30

1. Igneous 2. Sedimentary 3. Metamorphic ## Footnote Each rock type forms through different processes: *igneous* from cooling magma or lava, *sedimentary* from compacted sediments, and *metamorphic* from heat and pressure.

Question 31

# True or False: Igneous rocks form from the **cooling** of molten material.

Answer 31

True ## Footnote Both magma (beneath the surface) and lava (on the surface) cool and solidify to form igneous rocks like granite and basalt.

Question 32

Which rock **forms** from heat and pressure deep within Earth?

Answer 32

Metamorphic ## Footnote **Metamorphic** rocks, such as marble and slate, are created when existing rocks undergo heat and pressure.

Question 33

# Fill in the blank: Sedimentary rocks form from the **accumulation** of \_\_\_\_\_ and mud.

Answer 33

sand ## Footnote Sediments accumulate, are compacted over time, and eventually cement together to form solid sedimentary rock.

Question 34

Which igneous rock forms from **rapid** lava cooling?

Answer 34

Basalt ## Footnote **Basalt** is an extrusive igneous rock formed from quickly cooling lava at the Earth's surface, giving it a fine-grained texture.

Question 35

# True or False: Sedimentary rocks are usually **layered**.

Answer 35

True ## Footnote Sedimentary rocks are typically layered due to the gradual **accumulation** of sediments over time.

Question 36

What is the primary component of **limestone**?

Answer 36

Calcium carbonate ## Footnote Limestone is made primarily of *calcium carbonate*, often derived from marine organisms like corals and shells.

Question 37

What is an **example** of a metamorphic rock formed from limestone?

Answer 37

Marble ## Footnote **Marble** forms when limestone undergoes metamorphism due to heat and pressure, changing its mineral structure and appearance.

Question 38

# Fill in the blank: \_\_\_\_\_\_\_ is a **common** sedimentary rock that forms from compacted clay particles.

Answer 38

Shale ## Footnote **Shale** forms from the accumulation of fine clay particles and is often found in areas like riverbeds and lake bottoms.

Question 39

# True or False: Metamorphic rocks can be created from **both** igneous and sedimentary rocks.

Answer 39

True ## Footnote Metamorphic rocks are created when any type of rock (igneous, sedimentary, or even other metamorphic rocks) is **subjected** to heat and pressure.

Question 40

Which process is **responsible** for the formation of slate from shale?

Answer 40

Metamorphism ## Footnote Slate forms from shale through the process of **metamorphism**, where heat and pressure change its mineral structure.

Question 41

What is the **process** by which rocks are broken down into smaller pieces?

Answer 41

Weathering ## Footnote **Weathering** occurs due to physical, chemical, or biological forces, breaking down rocks into smaller particles.

Question 42

# Fill in the blank: \_\_\_\_\_\_\_ is the **movement** of weathered material by wind or water.

Answer 42

Erosion ## Footnote **Erosion** moves weathered materials to new locations where they may form new rocks or features.

Question 43

# True or False: Weathering and erosion are part of the **same** process in the rock cycle.

Answer 43

True ## Footnote Weathering *breaks* rocks down, while erosion *transports* the broken-down materials to new locations.

Question 44

What happens during the **deposition** of sediments?

Answer 44

**Sediments** settle and accumulate in layers. ## Footnote Deposition occurs when transporting agents (like water or wind) slow down, allowing the sediments to accumulate.

Question 45

What **process** turns sediment into sedimentary rock?

Answer 45

Lithification ## Footnote **Lithification** involves compaction and cementation of sediment particles, forming solid sedimentary rocks.

Question 46

What **process** occurs when rocks melt into magma?

Answer 46

Melting ## Footnote **Melting** is essential for the formation of igneous rocks, as it allows solid rocks to become molten material (magma).

Question 47

Which rock is formed from the **accumulation of compacted sand grains**?

Answer 47

Sandstone ## Footnote **Sandstone** forms when sand particles are compacted and cemented together, often in deserts or beach environments.

Question 48

# True or False: Fossils are commonly found in **metamorphic** rocks.

Answer 48

False ## Footnote Fossils are more commonly found in **sedimentary** rocks, as these rocks form from the accumulation of materials that may contain ancient organisms.

Question 49

What type of rock is found in **mountain ranges formed by tectonic forces**?

Answer 49

Metamorphic ## Footnote **Metamorphic** rocks are often found in mountain ranges due to the heat and pressure from tectonic forces that alter the original rock.

Question 50

# Fill in the blank: \_\_\_\_\_\_\_\_ forms from the **slow cooling of magma** beneath the Earth's surface.

Answer 50

Granite ## Footnote **Granite** is an intrusive igneous rock with large crystals, formed when magma cools slowly beneath the surface.