GLY 3202
Which of these mineral formulae contain coupled substitutions. Fe is 2+ unless specified otherwise. [Select all that apply]
(Na, Ca)(Fe3+, Fe2+,Mg)Si2O6
Given that Si forms a 4+ ion and O forms a 2- ion, which formula represents the anionic group defining the silicate group of minerals?
(SiO4)4-
What is the electrostatic valence bond strength for Fe3+ in 6-fold coordination with O2-?
0.5
Given that potassium has an atomic no. 19 and 4 electron shells with the following configuration for the first 3 shells: Shell 1: 2 Shell 2: 8 Shell 3: 8 What charge does K have when it bonds with other elements?
1+
How many Ca ions are required to balance the mineral formula: CaXMg4Al(AlSi7)O22(OH)2? Valence states: Ca2+, Mg2+, Al3+, Si4+, O2-, H+
2
A mineral can be scratched by materials with a hardness of 8 and 9, but cannot be scratched by materials with a hardness of 6 and 7 on Mohs Scale. What is the hardness of the mineral?
7
What is the total number of cations in one complete formula of garnet: Mg3Al2(SiO4)3? Include multiples of cations in the formula in your count of the total.
8
What is a mineral?
A natural crystalline compound with a definite, but not fixed composition
What is an inference/interpretation?
A relatively subjective conclusion based on analysis of information.
Which physical property is described using the following terms? Botryoidal Granular
Aggregation
What is a cation?
An atom that has lost at least one electron.
What is a valence electron?
An electron in the outer shell of an atom available for bonding.
What is average speed of lithospheric plates?
Approximately 5 centimeters per year
What is a mineral crystal lattice?
Atoms and groups of atoms arranged in a 3D repeating pattern.
Complete solid solution is limited to certain temperatures and pressures in feldspars where Na is substituting for K. Why is this solid solution restricted?
Because K is a different size to Na
Why do hotspots or mantle plumes often form linearly arranged volcanic features such as island chains?
Because plates move over plumes that are stationary in the mantle.
Why do atoms bond?
Because they are most stable when they achieve a full outer shell of electrons.
Where in the Earth's interior is the MOHO?
Boundary between crust and mantle
Which chemical classification do these minerals belong to? Aragonite CaCO3; Dolomite CaMg(CO3)2; Magnesite MgCO3
Carbonates
What is the primary control on coordination number?
Cation and anion radius ratio
What are the two basic parameters that determine ease of substitution of cations in an atomic structure? [Select two]
Cation size Cation charge
How do cations and anions bond in mineral structures?
Cations bond with as many anions as possible based on radius constraints.
Which pair of minerals are the most difficult to tell apart in hand specimen?
Clinopyroxene and orthopyroxene.
What physical property easily distinguishes between quartz and olivine for the most common varieties of both minerals?
Color
How are minerals classified into the different chemical classes?
Composition of anionic group in the chemical formula
A mineral breaks to form an irregular pattern that resembles the interior of a sea-shell. What is the correct term for this?
Conchoidal fracture.
Magma is stored beneath a volcano prior to eruption. What kind of metamorphism could occur to the rocks adjacent to the magma chamber?
Contact
What is the primary mechanism of heat transfer in the mantle?
Convection
Which process is more efficient at transferring heat through the Earth's interior?
Convection
Which type of bonding involves sharing electrons between individual atoms?
Covalent
How do the properties of covalent bonds compare to ionic bonds?
Covalent bonds are generally more stable than ionic bonds.
Which of the Earth's layers has the lowest density?
Crust
What shape/volume represents 8-fold coordination?
Cube
Which type of boundary is associated with upwelling of mantle convection cells?
Divergent boundary
True or false? Only minerals harder than the porcelain streak plate will leave a streak on the plate when the streak test is applied.
False
True or false? There are an infinite number of patterns for arranging atoms in crystal lattices.
False
What distinguishes feldspars from quartz?
Feldspar has cleavages whereas quartz has no cleavages.
How is the Earth's magnetic field generated?
Flow of the liquid outer core
For the mineral olivine (Mg,Fe)2SiO4 the end-members are forsterite Mg2SiO4 and fayalite Fe2SiO4. What is the correct way to write the mineral formula in terms of end-members for an olivine with 25% Mg and 75% Fe?
Fo0.25Fa0.75
Which of the following is TRUE about cation size vs coordination numbers?
For a given anion, the coordination number can vary depending on the cation size
What is the definition of a subhedral crystal?
Good crystal shape with some good faces, but some faces inhibited by adjacent crystal growth
Which physical property is a measure of how resistant mineral crystals are to being scratched?
Hardness
Which physical properties of minerals are dependent on the strength or type of bonding? [Select all that apply]
Hardness, susceptibility to weathering, electrical conductivity, cleavage or fracture, solubility, melting point
In contact metamorphism, which of the following is the PRIMARY metamorphic agent in action?
Heat
Which of the following is NOT a mineral according to the definition presented in the book and lecture?
Ice (solid water)
How are mineral formulae constructed?
In order of decreasing coordination number
How does the thickness of the oceanic lithosphere change with distance from the ridge axis?
Increases
Classify this statement about an unknown mineral as an observation, interpretation, hypothesis or theory. Statement: The surface of the mineral when it breaks is irregular therefore, it does not have cleavage.
Interpretation/Inference
Which type of bonding involves the gain and loss of electrons between individual atoms?
Ionic
What are the building blocks of minerals?
Ions
You visit another star and planetary system and find that all the planets are composed of hydrogen and helium. What does this indicate about the star at the center of the system?
It is a first generation star
Which of the following is the first step in the process of identifying an unknown mineral sample?
Make observations
What ultimately drives plate tectonics?
Mantle convection
A mineral has a red streak. Is it more likely to be metallic or non-metallic?
Metallic
Which type of bonding involves sharing electrons on a lattice scale - not just between individual atoms?
Metallic
A mineral has a high Specific Gravity. Which of these two descriptions could you reasonably assume and almost always be correct?
Metallic luster
Which letter on the diagram marks the most productive rock factory? Green represents oceanic lithosphere and blue continental.
Mid ocean ridges
What is the general relationship between mineral hardness and the type of chemical bonding?
Mineral hardness increases with increasing % of covalent bonding.
What are end-members in the context of solid solution?
Minerals that represent the extremes of composition that can be achieved by elemental exchange.
What are polymorphs?
Minerals with identical compositions and different internal atomic structure
How does the composition of the ocean crust compare to the continental crust?
More homogeneous
Which letter on the diagram marks a continental arc? Green represents oceanic lithosphere and blue continental.
Mountains
Where would one expect to find the oldest oceanic lithosphere on any given lithospheric plate?
Near the continent
Amber has the following characteristics: hard, brittle, orange, indefinite composition, resinous, amorphous and smooth. Is amber a mineral?
No
Which property is unique to each chemical element?
Number of protons
Classify this statement about an unknown mineral as an observation, interpretation, hypothesis or theory. Statement: The mineral breaks into smaller rhombohedral shapes.
Observation
A cation is bonded with 6 anions. What is the shape of the volume enclosed by the surrounding anions (coordination polyhedron)?
Octahedron
Given the radius of Mg as 0.86 and O as 1.26 what coordination polyhedron would you predict using the following table?
Octahedron
Which of the following minerals contains more than one type of anionic group?
Orthoamphibole Talc
In regional metamorphism, which of the following is(are) the PRIMARY metamorphic agent(s) in action?
Pressure and temperature
What happens during solid solution?
Replacement of cations with other cations that are a similar size and maintain an electrically neutral crystal
Is gabbro a rock or a mineral?
Rock
Which bond will be the hardest to break? [Ca2+, Si4+, Al3+, O2-]
Si-O in 4-fold coordination
Given that in olivine, Si4+ is in 4-fold coordination with O2- and Mg2+ is in 6-fold coordination with O2- - which bond is stronger? Si-O or Mg-O?
Si-O is stronger
Which group of minerals are the most common and most abundant rock forming minerals?
Silicates
What is the difference between simple twinning and polysynthetic twinning?
Simple twinning involves one contact plane whereas polysynthetic twinning involves multiple contact planes.
How are chemical elements made?
Stellar processes
Which physical property describes the color of a mineral when powdered?
Streak
a=b≠c;α=β=γ=90∘
Tetragonal
Given the radius of Na as 1.26 and O as 1.26 what coordination polyhedron would you predict using the following table?
Tetrahedron
What is chemical differentiation?
The process of separating out elements based on physical or chemical properties
What defines the strength of an electrostatic valence bond?
The strength is the cation charge divided by the coordination number
What are the units of Specific Gravity (SG)?
There are no units. SG is dimensionless.
What do the chemical formulas indicate about this group of minerals? Orthoclase KAlSi3O8 Microcline KAlSi3O8 Sanidine KAlSi3O8
They form at different pressures and temperatures.
What are crystallographic axes?
Three of four lines parallel to the major lattice planes whose origin lies in the center of the crystal.
Which of these describes radiation?
Transfer of heat as electromagnetic waves
True or false? A rock can be made of multiple crystals of one mineral. Group of answer choices
True
True or false? A silica tetrahedron is composed of one Si atom bonded with four oxygen atoms.
True
True or false? Ion charge is a major control on crystal structure.
True
True or false? Ionic size is a major control on crystal structure.
True
True or false? There are alternative quantitative analytical methods to the petrographic microscope for identifying minerals.
True
Mid-ocean ridges experience a high degree of hydrothermal circulation of seawater through the crust that can alter mineral compositions. Is this considered metamorphism?
Yes
Quartz has a hardness of 7, while halite has a hardness of 4. Can you predict which one has the highest proportion of covalent bonding in its internal structure?
Yes, quartz has more covalent bonding.
What is the lithosphere composed of?
crust and upper mantle
What is the PRIMARY mechanism that generates magma in subduction zones?
from the subducting slab migrates to the mantle causing it to melt.
Is halite a rock or a mineral?
mineral
Is olivine a rock or a mineral?
mineral
Is quartz a rock or a mineral?
mineral
Is granite a rock or a mineral?
rock
Which type of bonding does not involve the sharing or exchange of electrons?
van der Waals
