4B2 Earth's Minerals and Rocks Flashcards
Explain how minerals have distinct properties, and how rocks undergo transformation through the rock cycle.
Define:
Mineral
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.
What is the most abundant mineral in Earth’s crust?
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.
True or False:
Rocks are made of one or more minerals.
True
Rocks are aggregates of minerals and may also contain organic material. For example, granite is composed of quartz, feldspar, and mica.
What property measures a mineral’s resistance to scratching?
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.
What property describes the way a mineral reflects light?
Luster
Luster can be metallic (shiny like metal) or non-metallic (e.g., glassy, pearly, or dull).
True or False:
Streak is the color of a mineral in powdered form.
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.
What property involves the way a mineral breaks along flat planes?
Cleavage
Cleavage occurs when minerals break along specific planes of weakness. The number and quality of cleavage planes vary by mineral type.
What refers to a mineral’s mass per unit volume?
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.
Fill in the blank:
Minerals with no defined cleavage exhibit ________.
fracture
Fracture describes irregular breaks in minerals. Examples include conchoidal (shell-like) fracture in quartz and splintery fracture in asbestos.
True or False:
All minerals are inorganic.
True
By definition, minerals are naturally occurring, inorganic substances with a definite chemical composition and crystalline structure.
What type of cleavage does calcite exhibit?
Rhombohedral
Calcite breaks into rhombohedron-shaped fragments due to its three planes of cleavage not intersecting at right angles.
What property describes the ability of a mineral to transmit light?
Transparency
Minerals can be transparent (clear, light passes through), translucent (light diffuses), or opaque (no light passes through).
What scale is used to measure mineral hardness?
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.
Fill in the blank:
A mineral’s ______ ______ is its natural shape when formed under ideal conditions.
crystal habit
Crystal habit describes a mineral’s external shape, such as prismatic (quartz) or cubic (pyrite), reflecting its internal atomic arrangement.
What mineral property causes magnetite to attract a magnet?
Magnetism
Magnetite, a common magnetic mineral, is strongly attracted to magnets, making it easily identifiable.
True or False:
Fluorescence is a property where minerals glow under ultraviolet light.
True
Fluorescent minerals like fluorite emit visible light when exposed to UV radiation due to their specific chemical composition.
What is the main cause of mineral color?
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).
What mineral is commonly used to test for a hardness of 3?
Calcite
Calcite can be scratched with a copper coin, making it an ideal reference for Mohs hardness of 3.
What mineral is the hardest on the Mohs scale?
Diamond
Diamond is rated 10 on the Mohs scale due to its strong covalent bonds in a tetrahedral crystal structure.
Fill in the blank:
Hematite leaves a ____ streak despite appearing metallic gray.
red
Hematite’s reddish streak is a reliable identifier, contrasting its metallic surface appearance.
What mineral is known for its perfect cubic cleavage?
Halite
Halite (rock salt) breaks along three perpendicular planes, forming perfect cubes.
What mineral has a pearly luster and cleaves into thin sheets?
Mica
Mica minerals, like muscovite and biotite, exhibit sheet-like cleavage due to their layered atomic structure.
Which mineral fizzes in acid and is often found in sedimentary rocks?
Calcite
Calcite reacts with dilute acid, releasing carbon dioxide. It is a common mineral in limestone and marble.
True or False:
Graphite and diamond are made of the same element.
True
Both graphite and diamond are forms of carbon. Their differing properties result from variations in atomic bonding and structure.
Fill in the blank:
Minerals that break into rough, uneven surfaces exhibit ________.
fracture
Fracture occurs when minerals lack planes of weakness. Quartz is a common example with conchoidal (curved) fractures.
What property makes gold ideal for jewelry?
Malleability
Gold’s malleability allows it to be shaped into thin sheets or intricate designs without breaking.
What is the lightest mineral in terms of density?
Graphite
Graphite is light and has a low density due to its layered structure with weak interlayer bonds.
True or False:
Quartz has no cleavage.
True
Quartz fractures rather than cleaves due to its strong atomic bonds in all directions, producing conchoidal (shell-like) surfaces.
What is the rock cycle?
A continuous process that transforms rocks through geological processes.
The rock cycle shows how rocks are recycled over time due to processes like weathering, melting, and cooling.
What are the three main types of rocks?
- Igneous
- Sedimentary
- Metamorphic
Each rock type forms through different processes: igneous from cooling magma or lava, sedimentary from compacted sediments, and metamorphic from heat and pressure.
True or False:
Igneous rocks form from the cooling of molten material.
True
Both magma (beneath the surface) and lava (on the surface) cool and solidify to form igneous rocks like granite and basalt.
Which rock forms from heat and pressure deep within Earth?
Metamorphic
Metamorphic rocks, such as marble and slate, are created when existing rocks undergo heat and pressure.
Fill in the blank:
Sedimentary rocks form from the accumulation of _____ and mud.
sand
Sediments accumulate, are compacted over time, and eventually cement together to form solid sedimentary rock.
Which igneous rock forms from rapid lava cooling?
Basalt
Basalt is an extrusive igneous rock formed from quickly cooling lava at the Earth’s surface, giving it a fine-grained texture.
True or False:
Sedimentary rocks are usually layered.
True
Sedimentary rocks are typically layered due to the gradual accumulation of sediments over time.
What is the primary component of limestone?
Calcium carbonate
Limestone is made primarily of calcium carbonate, often derived from marine organisms like corals and shells.
What is an example of a metamorphic rock formed from limestone?
Marble
Marble forms when limestone undergoes metamorphism due to heat and pressure, changing its mineral structure and appearance.
Fill in the blank:
_______ is a common sedimentary rock that forms from compacted clay particles.
Shale
Shale forms from the accumulation of fine clay particles and is often found in areas like riverbeds and lake bottoms.
True or False:
Metamorphic rocks can be created from both igneous and sedimentary rocks.
True
Metamorphic rocks are created when any type of rock (igneous, sedimentary, or even other metamorphic rocks) is subjected to heat and pressure.
Which process is responsible for the formation of slate from shale?
Metamorphism
Slate forms from shale through the process of metamorphism, where heat and pressure change its mineral structure.
What is the process by which rocks are broken down into smaller pieces?
Weathering
Weathering occurs due to physical, chemical, or biological forces, breaking down rocks into smaller particles.
Fill in the blank:
_______ is the movement of weathered material by wind or water.
Erosion
Erosion moves weathered materials to new locations where they may form new rocks or features.
True or False:
Weathering and erosion are part of the same process in the rock cycle.
True
Weathering breaks rocks down, while erosion transports the broken-down materials to new locations.
What happens during the deposition of sediments?
Sediments settle and accumulate in layers.
Deposition occurs when transporting agents (like water or wind) slow down, allowing the sediments to accumulate.
What process turns sediment into sedimentary rock?
Lithification
Lithification involves compaction and cementation of sediment particles, forming solid sedimentary rocks.
What process occurs when rocks melt into magma?
Melting
Melting is essential for the formation of igneous rocks, as it allows solid rocks to become molten material (magma).
Which rock is formed from the accumulation of compacted sand grains?
Sandstone
Sandstone forms when sand particles are compacted and cemented together, often in deserts or beach environments.
True or False:
Fossils are commonly found in metamorphic rocks.
False
Fossils are more commonly found in sedimentary rocks, as these rocks form from the accumulation of materials that may contain ancient organisms.
What type of rock is found in mountain ranges formed by tectonic forces?
Metamorphic
Metamorphic rocks are often found in mountain ranges due to the heat and pressure from tectonic forces that alter the original rock.
Fill in the blank:
________ forms from the slow cooling of magma beneath the Earth’s surface.
Granite
Granite is an intrusive igneous rock with large crystals, formed when magma cools slowly beneath the surface.
