What is the coarse-grained, intrusive (plutonic) equivalent of basalt?
- Gabbro
- Rhyolite
- Pumice
- Dacite
Explanation: Gabbro shares the same mafic composition as basalt but cools slowly deep underground, creating large mineral crystals.
Slate is a fine-grained, foliated metamorphic rock formed directly by the alteration of?
- Basalt
- Limestone
- Shale
- Granite
Explanation: When the fine-grained sedimentary rock shale is subjected to relatively low-grade metamorphism, it transforms into slate.
What type of metamorphism occurs when host rocks are baked by intruding magma?
- Contact metamorphism
- Regional metamorphism
- Dynamic metamorphism
- Shock metamorphism
Explanation: Contact metamorphism happens locally when pre-existing rocks are subjected to the intense heat of an adjacent magma body.
Which physical property describes the way a mineral's surface reflects light?
- Streak
- Fracture
- Luster
- Cleavage
Explanation: Luster refers to the quality and intensity of light reflected from the surface of a mineral (e.g., metallic or non-metallic).
Which of the following minerals serves as the world's primary ore of aluminum?
- Bauxite
- Galena
- Sphalerite
- Hematite
Explanation: Bauxite is a sedimentary rock with a relatively high aluminum content, making it the principal ore of aluminum.
Which of these rocks is primarily composed of volcanic ash and debris?
- Basalt
- Pumice
- Tuff
- Obsidian
Explanation: Tuff is a type of extrusive igneous rock made of volcanic ash ejected from a vent during an eruption, which then compacts and solidifies.
Basalt, which forms the majority of the oceanic crust, is an example of?
- Extrusive igneous
- Clastic sedimentary
- Intrusive igneous
- Foliated metamorphic
Explanation: Basalt is an extrusive (volcanic) igneous rock formed by the rapid cooling of lava on or near the Earth's surface.
According to the Mohs scale, which is the hardest naturally occurring mineral?
- Quartz
- Corundum
- Diamond
- Topaz
Explanation: Diamond defines the maximum value of 10 on the Mohs scale of mineral hardness.
The continuous transformation of one rock type into another is scientifically described by?
- The rock cycle
- Bowen's reaction
- Continental drift
- Lithification
Explanation: The rock cycle is the geological concept describing the time-consuming transitions through geologic time among the three main rock types.
Igneous rocks that are highly rich in silica and aluminum are classified as?
- Felsic rocks
- Mafic rocks
- Intermediate rocks
- Ultramafic rocks
Explanation: Felsic rocks (like granite and rhyolite) are rich in lighter elements such as silicon, oxygen, aluminum, sodium, and potassium.
Which of these minerals serves as the primary natural ore of lead?
- Bauxite
- Galena
- Hematite
- Sphalerite
Explanation: Galena (lead sulfide) is a heavy, silver-gray mineral that is the world's primary source and ore of lead.
Pumice is a highly vesicular volcanic rock notable primarily because it can?
- Dissolve easily
- Conduct electricity
- Scratch diamond
- Float on water
Explanation: Pumice contains so many trapped gas bubbles (vesicles) that its overall density is less than that of water, allowing it to float.
What is the primary mineral constituent that makes up limestone?
- Gypsum
- Calcite
- Feldspar
- Quartz
Explanation: Limestone is predominantly composed of the mineral calcite (calcium carbonate), often originating from marine biological debris.
Which common iron sulfide mineral is famously known as 'fool's gold'?
- Hematite
- Pyrite
- Chalcopyrite
- Galena
Explanation: Pyrite has a brass-yellow color and metallic luster that has historically caused prospectors to mistake it for real gold.
Which of the following serves as a classic example of a chemical sedimentary rock?
- Chert
- Breccia
- Shale
- Sandstone
Explanation: Chert is a hard, dark, opaque chemical sedimentary rock composed of microcrystalline quartz, formed by chemical precipitation.
Gneiss is a high-grade, distinctly banded metamorphic rock typically formed from?
- Granite
- Sandstone
- Shale
- Limestone
Explanation: When granite undergoes intense, high-grade metamorphism, its minerals separate into distinct alternating light and dark bands, forming gneiss.
What is the primary process of rocks breaking down in place without movement?
- Erosion
- Deposition
- Weathering
- Lithification
Explanation: Weathering is the in-situ (in place) physical breakdown and chemical alteration of rocks and minerals at or near the Earth's surface.
Fossils are almost exclusively preserved in which major type of rock?
- Plutonic
- Metamorphic
- Igneous
- Sedimentary
Explanation: Fossils are found in sedimentary rocks because the high heat and pressure involved in forming igneous and metamorphic rocks typically destroy organic remains.
According to the Mohs scale, what is the second hardest naturally occurring mineral?
- Corundum
- Fluorite
- Quartz
- Topaz
Explanation: Corundum has a hardness of 9, making it the second hardest mineral on the Mohs scale, just below diamond (10).
Which common igneous rock features a very coarse-grained texture due to slow underground cooling?
- Basalt
- Pumice
- Rhyolite
- Granite
Explanation: Granite cools slowly deep within the Earth, providing ample time for large, visible mineral crystals to develop.
Which extremely soft mineral defines a hardness of 1 on the Mohs scale?
- Gypsum
- Fluorite
- Talc
- Calcite
Explanation: Talc is the softest known mineral and serves as the baseline value of 1 on the Mohs hardness scale.
What type of metamorphism is primarily associated with large-scale mountain building?
- Burial metamorphism
- Contact metamorphism
- Thermal metamorphism
- Regional metamorphism
Explanation: Regional metamorphism occurs over vast areas, driven by the intense pressures and temperatures associated with tectonic plate collisions.
The complex process of loose sediments compacting and turning into solid rock is?
- Weathering
- Crystallization
- Lithification
- Metamorphism
Explanation: Lithification involves compaction and cementation, converting loose, unconsolidated sediment into solid sedimentary rock.
Igneous rocks that solidify at shallow depths below the surface are termed?
- Hypabyssal rocks
- Metamorphic rocks
- Volcanic rocks
- Plutonic rocks
Explanation: Hypabyssal (or subvolcanic) rocks form from magma that cools at shallow depths, resulting in medium-grained textures (e.g., dolerite).
Amphibolite is a medium-to-high-grade metamorphic rock typically derived from?
- Sandstone
- Shale
- Limestone
- Basalt
Explanation: Amphibolite forms primarily through the regional metamorphism of mafic igneous rocks like basalt or gabbro.
The true color of a mineral when observed in its powdered form is its?
- Streak
- Luster
- Fracture
- Cleavage
Explanation: Streak is determined by rubbing a mineral across an unglazed porcelain plate; it is more reliable for identification than the mineral's surface color.
Conversely, igneous rocks rich in magnesium and iron are classified as?
- Silicic rocks
- Mafic rocks
- Plutonic rocks
- Felsic rocks
Explanation: Mafic rocks (like basalt and gabbro) are dark-colored igneous rocks rich in heavier elements like magnesium and iron.
Which sedimentary rock typically exhibits very high porosity and permeability?
- Shale
- Sandstone
- Slate
- Granite
Explanation: Sandstone is highly porous and permeable, making it one of the most important reservoir rocks for groundwater and petroleum.
Which rock is formed by the slow cooling of magma deep inside the Earth?
- Metamorphic rock
- Volcanic igneous
- Plutonic igneous
- Sedimentary rock
Explanation: Plutonic (intrusive) igneous rocks form when magma cools slowly beneath the Earth's surface, allowing large crystals to grow.
Which mineral is the primary constituent of both limestone and marble?
- Dolomite
- Aragonite
- Calcite
- Siderite
Explanation: Calcite (calcium carbonate) is the dominant mineral in both the sedimentary rock limestone and its metamorphic equivalent, marble.
A clastic sedimentary rock composed primarily of large, angular fragments is called?
- Sandstone
- Conglomerate
- Siltstone
- Breccia
Explanation: Breccia is formed from coarse, angular rock fragments cemented together, indicating they were deposited close to their source.
Which bright red mineral serves as the primary natural ore of mercury?
- Cinnabar
- Magnetite
- Pyrite
- Galena
Explanation: Cinnabar (mercury sulfide) is a toxic, bright red mineral that has been mined for centuries as the chief source of mercury.
A clastic sedimentary rock composed primarily of large, rounded fragments is called?
- Breccia
- Conglomerate
- Shale
- Mudstone
Explanation: Conglomerate is made of rounded gravel or pebbles, indicating the clasts were transported and smoothed by water before deposition.
What is generally considered the second most abundant mineral in the Earth's crust?
- Feldspar
- Amphibole
- Olivine
- Quartz
Explanation: Quartz (silicon dioxide) makes up about 12% of the continental crust, making it the second most abundant mineral after feldspar.
Magma that successfully breaches the Earth's crust and reaches the surface is called?
Explanation: Lava is molten rock generated by geothermal energy and expelled through fractures in planetary crust or an eruption.
What is the fine-grained, extrusive (volcanic) equivalent of granite?
- Basalt
- Gabbro
- Andesite
- Rhyolite
Explanation: Rhyolite has the same felsic mineral composition as granite but cools rapidly at the surface, giving it a fine-grained texture.
Quartzite is a hard, non-foliated rock metamorphosed from which parent rock?
- Sandstone
- Basalt
- Granite
- Limestone
Explanation: Quartzite is formed when quartz-rich sandstone is altered by high heat and pressure, fusing the quartz grains together.
Which geological process involves the transportation of weathered rock material by wind or water?
- Crystallization
- Lithification
- Deposition
- Erosion
Explanation: Erosion is the surface process that removes soil, rock, or dissolved material from one location and transports it to another.
What is the single most abundant mineral found within the Earth's continental crust?
- Calcite
- Feldspar
- Mica
- Quartz
Explanation: Feldspars are a group of rock-forming tectosilicate minerals that make up approximately 41% of the Earth's continental crust by weight.
Which of the following serves as a classic example of a clastic sedimentary rock?
- Chalk
- Rock salt
- Sandstone
- Coal
Explanation: Clastic rocks are formed from the weathered fragments (clasts) of pre-existing rocks. Sandstone is a primary example.
What term describes a mineral's inherent tendency to break along specific flat planes?
- Cleavage
- Streak
- Fracture
- Hardness
Explanation: Cleavage is the tendency of a crystalline substance to split into fragments bounded by planar surfaces corresponding to weak atomic bonds.
Which coal variety represents the highest grade of metamorphism?
- Bituminous coal
- Peat bog
- Anthracite coal
- Lignite coal
Explanation: Anthracite is a hard, compact variety of coal that has the highest carbon content and represents the highest grade of coal metamorphism.
On the Mohs scale of mineral hardness, which mineral defines a hardness of 3?
- Calcite
- Talc
- Gypsum
- Fluorite
Explanation: Calcite is the standard index mineral for a hardness of 3 on the Mohs scale.
Which dominant mineral group makes up over 90% of the Earth's crust?
- Silicates
- Carbonates
- Sulfates
- Halides
Explanation: Silicate minerals, composed primarily of silicon and oxygen, are the fundamental rock-forming minerals of the Earth's crust.
What is the most abundant chemical element found in the Earth's crust?
- Aluminum
- Iron
- Oxygen
- Silicon
Explanation: Oxygen is the most abundant element in the Earth's crust, making up about 46.6% of its weight, primarily in silicate minerals.
Which intrusive igneous rock forms the deep, lower layers of the oceanic crust?
- Granite
- Rhyolite
- Diorite
- Gabbro
Explanation: While basalt covers the surface of the ocean floor, the deep, slowly cooled lower layers of the oceanic crust are composed of gabbro.
Obsidian is an extrusive igneous rock uniquely characterized by its?
- Glassy texture
- Foliated structure
- Fossil content
- Coarse grains
Explanation: Obsidian forms from lava that cools so rapidly that crystal formation is impossible, resulting in a smooth, glassy texture.
Which dense, green silicate mineral is highly abundant in the Earth's upper mantle?
- Biotite
- Olivine
- Quartz
- Muscovite
Explanation: Olivine is an olive-green magnesium iron silicate that constitutes a massive portion of the Earth's upper mantle.
The distinct layering or bedding uniquely characteristic of sedimentary rocks is called?
- Lineation
- Cleavage
- Foliation
- Stratification
Explanation: Stratification refers to the way sedimentary rocks form in distinct, horizontal layers or strata over long periods of time.
Chalk is a very soft, white, porous variety of which sedimentary rock?
- Shale
- Limestone
- Conglomerate
- Sandstone
Explanation: Chalk is a form of limestone composed primarily of the microscopic shells of marine organisms called coccolithophores.
Foliation is a distinct structural texture that is exclusively associated with which rock type?
- Metamorphic
- Igneous
- Volcanic
- Sedimentary
Explanation: Foliation refers to the repetitive layering or banding in metamorphic rocks, caused by directed pressure during metamorphism.
The tendency of quartz and glass to break along smooth, curved surfaces is called?
- Uneven fracture
- Basal cleavage
- Perfect cleavage
- Conchoidal fracture
Explanation: Minerals without cleavage planes, like quartz, often exhibit conchoidal fracture, breaking with curved, shell-like ripples.
Which of the following is classified as a non-silicate mineral?
- Mica
- Halite
- Quartz
- Feldspar
Explanation: Halite (rock salt) is a halide mineral and does not contain the silicon-oxygen tetrahedrons that define silicate minerals.
Which of the following is considered an organically formed sedimentary rock?
- Shale
- Sandstone
- Breccia
- Coal
Explanation: Coal is an organic sedimentary rock formed from the compacted and altered remains of ancient plant material.
An igneous rock featuring two distinctly different crystal sizes has what texture?
- Glassy texture
- Phaneritic texture
- Aphanitic texture
- Porphyritic texture
Explanation: A porphyritic texture indicates a two-stage cooling process, resulting in large crystals (phenocrysts) embedded in a finer-grained groundmass.
Which specific mineral group reacts vigorously, effervescing when exposed to dilute hydrochloric acid?
- Sulfates
- Halides
- Carbonates
- Silicates
Explanation: Carbonate minerals, most notably calcite, fizz and release carbon dioxide gas when they come into contact with cold, dilute hydrochloric acid.
Which of these rocks is formed by the chemical precipitation of minerals from water?
- Conglomerate
- Rock salt
- Sandstone
- Breccia
Explanation: Rock salt (halite) is a chemical sedimentary rock that forms from the evaporation of mineral-rich water bodies.
Which term describes the fundamental, primary rocks from which all others are derived?
- Igneous rocks
- Metamorphic rocks
- Clastic rocks
- Sedimentary rocks
Explanation: Igneous rocks are considered primary rocks because they crystallize directly from magma or lava, forming the basis for the rock cycle.
Which common iron oxide mineral naturally exhibits strong magnetic properties?
- Magnetite
- Pyrite
- Limonite
- Hematite
Explanation: Magnetite is a highly magnetic iron ore; naturally magnetized pieces, called lodestones, were used as early compasses.
Marble is a metamorphic rock that originates from the metamorphism of?
- Shale
- Granite
- Limestone
- Sandstone
Explanation: Marble forms when limestone is subjected to immense heat and pressure, causing the calcite grains to recrystallize.