Geology #2

The mineral ___ reacts with weak hydrochloric acid to produce carbon dioxide gas, i.e., it effervesces (fizzes) in dilute acid.

calcite

Non-silicate minerals are more abundant in the deeper parts of Earth's crust than in the crust as a whole.

false

Rhyolite is considerably more common than granite.

false

Non-silicate minerals include the halides like _____.

halite

A silica tetrahedron is composed of four atoms of the element ___ and one atom of __.

oxygen/ silicon

_____, a coarse-grained rock composed of pyroxene and olivine, is the most abundant ultramafic rock.

peridotite

Five of the six minerals collectively known as asbestos contain single chains of silica tetrahedral and belong to the _______.

pyroxenes

Basaltic magmas crystallize at higher temperatures than granitic magmas.

true

The crystal form of a mineral is a set of faces that have a definite geometric relationship to one another.

true

The geothermal gradient for a volcanic region is greater than that for the continental interior.

true

A ______ is an intrusive structure that formed from magma that solidified within the "throat" of a volcano.

volcanic neck

The mineral ___ is strongly magnetic.

Magnetite

The _____ group of minerals are sheet silicates.

Mica

______ is an expansive (swells when wet) clay mineral.

Montmorillonite

______ are fragments of country rock that are distinct from the body of igneous rocks in which they are enclosed.

Xenoliths

The third most abundant element in the Earth's crust is ______; it is more common than iron.

aluminum

The ______ group of minerals is characterized by two parallel chains of silica tetrahedra in their structure.

amphibole

_______ are the smallest electrically neutral assemblies of matter and energy that we know of in the universe.

atoms

_____ is the ability of a mineral to break, when struck or split, along preferred planar directions.

cleavage

Both andesite and ___ are composed of feldspars and 30% to 50% ferromagnesian minerals.

diorite

____ elements make up 98% of the Earth's crust.

eight

Fine-grained igneous rocks (grains < 1.0 mm) that have small grains cooled rapidly and are likely to be _______.

extrusive

Igneous rocks may be either ____ if they form on or near Earth's surface, or ___ if they solidify under ground.

extrusive/ intrusive

A pluton is an igneous structure that crystallized at very shallow depths.

false

Although batholiths may contain mafic and intermediate rocks, they almost never composed of granite.

false

An ultramafic rock is composed almost entirely of quartz.

false

Clay minerals are very common in the Earth's upper mantle.

false

Diamond has no cleavage.

false

Extrusive igneous rocks are typically fine grained because they crystallized slowly, deep below the Earth's surface.

false

Igneous rock names are based on grain shape and chemical composition.

false

It is clear that exposure to white asbestos causes cancer among non-smoking asbestos workers.

false

Specific gravity is the ratio of a mass of a substance to the mass of an equal volume of air.

false

The atomic mass number is equal to the number of neutrons in an atom.

false

The continuous branch in Bowen's Reaction Series contains the ferromagnesian minerals.

false

The geothermal gradient is the rate at which pressure increases with increasing depth beneath the surface.

false

The innermost energy level in the standard model of an atom is full when it possesses eight electrons.

false

The melting point of a rock decreases with increasing pressure.

false

The number of neutrons in an atom controls the chemical behavior of an element.

false

The most common minerals in a granite are the ______.

feldspars

Ultramafic igneous rocks are composed almost entirely of __.

ferromagnesian minerals

In some minerals the bonds are equally strong in all directions, therefore they have no cleavage but instead _____ along irregular surfaces that are commonly curved.

fracture

___ is a coarse-grained igneous rock (grains > 1 mm diameter) with visible grains of quartz.

granite

______ is the predominant igneous rock of the continents.

granite

The mineral ___ is an example of a native element.

graphite

When seawater evaporates, its sodium and chlorine are electronically attracted to one another and crystallize into ___.

halite

_______ of an element are atoms containing different numbers of neutrons but the same number of protons.

isotopes

What is the special property of the mineral halite?

it tastes like salt

Specific gravity is the ratio of the mass of a mineral to the mass of an equal volume of __.

liquid water

___ are igneous rocks that are silica-deficient but high in iron and magnesium.

mafic

______ igneous rocks, like gabbro and basalt, are silica-deficient with high magnesium and iron.

mafic

Mineralogically and chemically equivalent rocks are ___ and __.

mafic/ ultramafic

The _____ group and the ___ group are sheet silicates characterized by one direction of cleavage.

mica/ clay

Carbon-14 has eight __.

neutrons

In order for a particular type of material to be classified as a mineral, it must ____.

occur naturally, have a crystalline structure, have a definite chemical composition, and be a solid

The common mineral ___ is an example of an isolated silica tetrahedron structure.

olivine

The isotope composition of _____ in foraminifera shells from sediment cores are used to determine climate change in Earth history.

oxygen

____ is the most common element in the Earth's crust.

oxygen

The two most abundant elements in Earth's crust are __.

oxygen and silicon

Some minerals have the same chemical composition but different crystal structures, a phenomenon termed _______.

polymorphism

The atomic number of an element equals the number of _____ in each atom.

protons

The atomic mass number of an atom is the total number of ___ in the atom.

protons and neutrons

____ has the property of generating electricity when squeezed in a certain crystallographic direction.

quartz

Two examples of framework silicates are _____ and ______.

quartz/ feldspar

A useful tool illustrating the relationships among igneous, sedimentary, and metamorphic rocks is called the ___.

rock cycle

_______ and sapphire are both varieties of the common mineral corundum.

ruby

The most common minerals in the Earth's crust are the _______.

silicates

Igneous rocks that are silica-rich with high aluminum, sodium, and potassium are _____ rocks.

silicic

A _______ is a tabular (thin but large area) intrusive body that is concordant (parallel to the host rock structure).

sill

____, a Danish naturalist, was the first to note that the angle between two adjacent faces of a crystal of quartz is always exactly the same.

steno

A pulverized mineral (usually on a piece of white unglazed porcelain) gives a color called its ____, that is usually more reliable than the color of the specimen itself.

streak

Plagioclase feldspar commonly exhibits __, straight, parallel lines on the flat surfaces of one of the two cleavage directions.

striations

The softest mineral on Mohs' hardness scale is ____.

talc

A dike is a discordant intrusive igneous structure.

true

A mineral is defined as a crystalline solid that is naturally occurring, has a specific chemical composition and forms through geologic processes.

true

A mineral specimen with a Mohs hardness of 5 can scratch a mineral specimen with a hardness of 3.

true

A mineral's melting point generally increases with increasing pressure.

true

All of the most common rock-forming minerals in Earth's crust are silicate minerals.

true

Both graphite and diamond are made of carbon.

true

Calcite (calcium carbonate) is the most common non-silicate mineral in the Earth's crust.

true

Color is the least reliable physical property in mineral identification.

true

Diorite and andesite are composed of similar amounts of feldspars and ferromagnesian minerals.

true

Lava is magma on the Earth's surface.

true

Mafic igneous rocks are silica-poor.

true

Minerals that have the same chemical composition but have different crystalline structures exhibit polymorphism

true

Partial melting of the lower continental crust produces a silicic magma that eventually solidifies into granite or rhyolite.

true

Pegmatites are extremely coarse-grained igneous rocks.

true

Rocks are defined as naturally-formed aggregates of minerals or mineral-like substances.

true

Silica is a term for oxygen combined with silicon.

true

The atomic number of an element is equal to the number of protons in each atom.

true

The quality and intensity of light that is reflected from the surface of a mineral is termed luster.

true

The sequence in which minerals crystallize in a cooling igneous melt is called Bowen's Reaction Series.

true

The term mafic comes from the terms magnesium and ferric.

true

The geothermal gradient, on average, is about _____.

30 C/km

Under ideal conditions rock can melt and yield a granite composition at temperatures as low as ___.

650 celcius

The atomic mass number of common oxygen is 16 because it has ___ protons and ___ neutrons.

8/8

The hardest mineral has a hardness of ___ on Mohs' relative hardness scale.

10

On Mohs' scale of hardness your fingernail has a value of ____.

2.5

Calcite has ___ direction of cleavage.

3

______ are extremely coarse-grained with crystal up to 10 meters across.

Pegmatites

_____ rocks have coarse crystals in a fine-grained matrix.

Porphyritic