Geology Chapter 4: Earth Materials

Which of the following are ways in which minerals are used for items typically found in a medicine cabinet?

-"scouring agents" in toothpast contain calcite -Emery boards have either garnet or corundum -Fluoride in toothpaste is derived from fluorite

What are two main ways that geologic minerals are used in society?

-As a source of elements and compounds that we use to manufacture other products -For some of their special properties, like color, density, and resistance to heat or abrasion, etc.

Polarity

-Dissolution of solids composed of anions and cations -Attraction to ions

What factors contribute to a water molecule having polarity?

-Electrons spend more time around the oxygen atom and give the molecule a negative side and two positive ends on the other side -Oxygen more strongly attracts electrons than hydrogen does Hydrogen atoms are grouped on one side of the oxygen atom

Which of the following are true of the properties of water?

-Hydrogen bonds form between water molecules and are responsible for the high surface tension of water -A water molecule is polar, and opposite ends of individual water molecules are attracted to anions and cations -Water can dissolve materials by breaking apart ionic bonds as polar water molecules attract individual ions away from each other

Non-silicate Minerals

-Include calcite, hematite, pyrite, gypsum, and halite -Do not contain silicon -Include the carbonates, oxides, sulfides, sulfates, and halides

Silicate Minerals

-Include quartz, feldspar, mica, olivine, and pyroxene -Account for over 90% of the minerals in Earth's crust -Contain silicon-oxygen tetrahedra

Hydrogen Bonding

-Surface tension -Viscosity

Which of the following help determine the outward shape of a crystal?

-The arrangement of atoms in the crystal -How the crystal's growth was affected by the material around it

A sillicon-oxygen tetrahedron__________.

-forms a building block for the vast majority of minerals on Earth -may join with other tetrahedra or cations to form different types of silicates and a wide variety of minerals -has one silicon atoms bonded with four oxygen atoms

Which of the following structures are commonly formed by silicon-oxygen tetrahedra?

-frameworks -independent tetrahedra -sheets -single and double chains

Why is the lower density of ice compared to liquid water so important?

-ice floats in water; if it didn't, lakes would freeze solid in winter as surface ice sinks to the bottom -it aids in weathering, as water that freezes and expands can pry apart rocks and soil

What happens at the atomic scale when a mineral cleaves or fractures?

-if all bonds have the same strength, they may be arranged in such a way that the mineral cleaves along three planes without passing through an atom -if different bonds between atoms have different strengths, the mineral will cleave along the weakest bond directions -if all bonds have the same strength, they may not be arranged in such a way as to allow cleavage planes to form; mineral fractures

Clay

-is a term that may be used as a particle size designation (less than 0.002mm) or to describe a family of minerals -minerals have a sheet-silicate structure, but atoms are bonded weakly -minerals form by weathering of rocks at Earth's surface or from chemical reactions in hot water

Which of the following are criteria that must be fulfilled for a substance to be considered a mineral?

-naturally occurring -inorganic -crystalline solid

Which of the following are true of the organization of rows and columns in the Periodic Table

-rows indicate the number of electron shells -elements in the first column have only one electron in their outer shell -elements in the last column are noble gases and have full outer shells

Rank the following in order to show the dissolution of halite in water. (first to last)

1. Halite crystals are immersed in water 2. The positive end of a water molecule becomes attracted to Cl anions, whereas the negative end of a water molecule becomes attracted to Na cations 3. When the attraction of the polar water molecule to various cations ans anions is strong enough, it pulls the ions away from the halite crystal 4.Na cations become surrounded by negative sides of water molecules and Cl anions become surrounded by positive sides of water molecules 5. As this process is repeated, the halite crystals are eventually dissolved in water.

Rank the following in order to show the precipitation of halite from water. (first event to last)

1. Salty water begins to evaporate 2. As water molecules move out of the liquid state, Na cations and CI anions become more concentrated and are left behind 3. Na cations and Ci anions become closer to each other and begin to bond 4. Resulting NaCl pairs combine and begin to organize into an ordered structure; a halite crystal

Rank the following earth materials in order of their most likely occurrence, starting at Earth's surface. Think about moving from the curst to the mantle, and then to the outer and inner core

1.)granite and basalt 2.) increasing amounts of olivine and pyroxene 3.) minerals stable at very high pressures; FE-MG silicates and oxides 4.) molten iron with nickel and some other elements 5.) crystalline iron and iron nickel alloy

Talc

Baby powder (from the softest mineral)

Calcite

CaCO3; most common calcium carbonate mineral; may be almost clear, but commonly cream to light gray; effervesces with dilute HCI

Dolomite

CaMg(CO3)2; cream, light tan, or brown; effervesces with dilute HCI when pulverized into a fine powder

A unknown mineral sample is scratched by copper wire, but not by a fingernail. Based upon the Mohs Hardness Scale, what is the likely identity of this mineral?

Calcite

two non-perpendicular directions

Cleaves along two set of planes that intersect at angles other than 90 degrees

Carbonates

Contain (CO3)^2; most important are calcite and dolomite; typically precipitate from water or originate organically

Sulfides

Contain (S)^-2 bonded with Fe, Pb, Zn, or Cu; principal metal ores in many mines; include pyrite and galena

Sulfates

Contain (SO4)^2- plus an element, such as Ca; many are evaporates or precipitates; include gypsum

Halides

Contain a metallic element, such as Na or K, and usually Cl; many are evaporates or precipitates; include halite

Oxides

Contain oxygen bonded with metals (most commonly and Fe); include ice, hematite, and magnetite

Silicate minerals that are rich in magnesium and iron are _______ colored

Dark

Smallest to largest

Electron, atomic nucleus, single atom of an element, mineral

Hematite

Fe2O3; black, brown, silvery gray, or earthy red; red streak; commonly forms when iron-bearing minerals oxidize

Magnetite

Fe3O4; typically black; strongly magnetic, present in many igneous, sedimentary, and metamorphic rocks, as well as in sands and sediments

Dolomite is very similar to calcite, but some of the calcium in its structure has been replaced with _________.

Magnesium

MicA

Makeup (as glitter)

Quartz

May be used for chemical components; the element silicon is used to create computer chips and is mostly derived from this mineral

Clays

May be used for its physical properties; this mineral is used to produce brick, cement, and ceramics

Hematile

Maybe be used for chemical components; iron is the main ingredient in steel and is mostly mined from minerals such as this

Independent Tetrahedra

Minerals (like olivine) do not break along clearly defined planes; all bonds are almost equally strong

Electrons

Negatively charged particles in orbit around the nucleus of an atom

Atomic Mass

Number of positively charged plus neutrally charged particles in an atom

Streak

Observe color left behind on a porcelain plate when mineral is dragged across it

Effervescence

Observe if a dilute HCI solution bubbles when placed on mineral

Magnetism

Observe if magnet sticks to mineral

Nucleus

Part of the atom that contains the protons and neutrons

Neutrons

Parts of the atom that do not have a charge

Protons

Parts of the atoms with a positive electrical charge

Water makes a good cleaning agent and solvent because it is able to dissolve materials due to its ____________

Polarity

Refers to the compound SiO2?

Silica(silicon dioxide)

frameworks

Tetrahedra share four O atoms; quartz with no cleavage, or feldspar with cleavage

Electron shells

The different energy states of negatively charged atomic particles arranged around the nucleus of an atom

Best describes the materials that cover Earth's surface

There are many different materials, and they vary by location

Trona and fluorite

Toothpaste

Hardness

Use of reference minerals and other standardized materials to see which are scratched by an unknown mineral and which are not

Why is ice less dense than water?

When water freezes, the molecules arrange into a crystal form in which they are farther apart than in liquid water

Pharmaceutical mineral

always composed of a single chemical element and Potassium (K)

Magnetite and hematite occur together in layered sedimentary rocks called __________

banded iron formations

An ion with a positive charge is called a(n) __________, whereas an ion with a negative charge is called a(n) ____________.

cation, anion

one direction

cleaves along one set of parallel planes, forming thin sheets

three non-perpendicular direction

cleaves along three sets of planes and the mineral commonly breaks into rhombs

three perpendicular direction

cleaves along three sets of planes and the minerals commonly breaks into cubes

two perpendicular directions

cleaves along two sets of planes that result in 90 degree steps along broken crystal faces

non-mineral

created in lab, organic composition (part of an animal or plant), and randomly arranged atoms

Over 90% pf Earths __________ is composed of silicate minerals.

crust

Which of the following are attributes that are evaluated to classify crystalline and clastic rocks?

crystal/clast shape, presence/absence of layers, minerals present, and crystal/clast size

hand specimen

different colored grains are present and minerals have different colors

The periodic table categorizes __________ based on their atomic number and chemical properties

elements

Crystalline

forms in high-temperature environments; minerals are interlocking

Clastic

forms in low-temperatures environments, at or near Earth's surface

double chains

half the tetrahedra share two O atoms and half share three; minerals cleave parallel to structure and along two planes at 60 degrees and 120 degrees

Of the four most abundant elements in the entire Earth, which is the most common?

iron

The most common minerals in the upper part of the continental crust are ________-colored silicates. They are felsic in composition, and their color is a direct result of their elemental composition

light

Thin Section

light passes through mineral crystals and internal structure of mineral crystals is seen

Which of the following mineral properties can be directly observed by the naked eye, without the need for testing supplies and equipment, and relate to the appearance of the mineral?

luster, color, crystal shape, cleavage/fracture

Clay minerals

makeup and foot powder

Gypsum

may be used for its physical properties; sheetrock and plaster products are made from this mineral

Geologists and other scientists who study minerals are called ____________.

mineralogists

In order for a crystal to attain a well-define shape it ______________

must grow unimpeded by surrounded material and likely grows in an open space, in water or in magma

The silicon-oxygen tetrahedron has _______ charge, and so attracts ______-

negative; cations

mineral

occurs naturally, ordered internal structure, and inorganic composition

A substance that has well-defined geometric crystals is likely to have a(n) __________ internal structure

ordered

Why are silicate minerals the most abundant in Earth's crust and mantle?

oxygen and silicon are the most common elements in Earth's crust and are two of the most common elements in Earth's mantle

Cliff face

rocks look homogeneous and rock appears to be one color

The ratio of density of a mineral to that of freshwater is called the mineral's _____________

specific gravity

sheets

tetrahedra share three oxygen atoms; cleavage of minerals (like micas and clays) is in one main direction

single chains

tetrahedra share two O atoms and are strongly bonded; cleavage is parallel to the bonded tetrahedra

This is the one word geologists use to describe how grains and minerals are arranged in a rock.

texture

If a mineral lacks planes along which it may cleave, what will occur?

the mineral will fracture in an irregular patter

There are more than 4,000 known minerals, most of which are

uncommon to rare

Geologic mineral

usually composed of two or more chemical elements and Halite (NaCl)