Rocks and Minerals
The first minerals to be mined.
What were flint and chert?
When Calcium (Ca) bonds with oxygen, it gives up two electrons. What is the charge of the Ca ion in this compound?
+2
The columns of the periodic table divide atoms by their ________.
number of valence electrons
What mineral is the hardest known substance in nature?
diamond
Which electrons are responsible for most chemical bonding?
Outer electron shell because these electrons can be readily exchanged with adjacent atoms
Atoms that have an electrical charge due to a gain or loss of electrons are called ________.
ions
Angles are important when looking at which physical properties of minerals?
cleavages
The most common group of silicates is ________.
feldspar
What is not a common rock forming mineral?
carbon
Which mineral group exhibits a sheet-like silicate structure?
micas
Ore deposits of the element ________ do not require extreme concentrations because it is one of the most abundant elements in the Earth's crust.
aluminum
Why is salt considered a mineral according to geologists?
Naturally occurring, inorganic, & orderly crystalline structure
What denotes the positively charged particles in an atom's nucleus?
protons
The bond between two hydrogen atoms (a covalent bond) is based on the force of attraction between ________.
protons in the nuclei and electrons surrounding the nuclei
The resistance of a mineral to abrasion is known as ________.
hardness
Atoms that have share electrons have what kind of bond?
What is covalent?
One significant difference between an ionic bond, where electrons are taken from one atom and added to another atom, and a covalent or metallic bond, where electrons are shared, is ________.
ionic bonds produce ions but covalent and metallic bonds do not produce ions
The mineral fluorite is commonly sold in mineral shops as octahedral (8-sided) objects. This shape originates from ________.
cutting a larger crystal along four perfect cleavage planes, forming a cleavage fragment
Dark Silicates have a specific gravity of 3.2 to 3.6 and are composed primarily of silica tetrahedral and ________.
iron and magnesium
Carbonates always include ________.
CO3-2
There are people who specialize in "cutting" diamonds, yet diamond is the hardest known substance. From your knowledge of minerals, which of the following describes what the diamond cutter does?
Diamond has more than one cleavage, and the cutter looks for small cracks along the cleavage and uses a chisel to break the mineral along the cleavage.
Gold is one of the rarest elements in the universe, yet it is extracted from ores on Earth. How is this possible?
Gold does not bond with other elements and the native metal is extremely concentrated in the Earth's crust, which allows it to be extracted from rocks but low concentrations still contribute to its low price.
Why is limestone considered a rock?
composed almost entirely of calcite, which has a chemical formula of CaCO3
These are the fundamental particles of an atom.
What are neutron, electron, & proton?
Using the Periodic Table, Be is to Mg as ________.
K is to Rb
Which mineral reacts readily with cool, dilute hydrochloric acid to produce visible bubbles of carbon dioxide gas?
Calcite
Heavy elements like Pb (lead) and U (Uranium) were generated during what?
During collapse of a star and subsequent nuclear synthesis in a supernova
The most unreliable (variable) diagnostic property of minerals such as quartz is ________.
color
Halides always include ________.
Cl-1, F-1, or Br-1
Silicates most commonly form from ________.
cooling molten rock
Gypsum, which is widely used in plaster and wallboard, is a member of the ________ group.
sulfate
Talc and graphite are two of the lowest minerals on the hardness scale. They are also described by terms like greasy or soapy. Both have a crystal structure characterized by sheet-structures at the atomic level, yet they don't behave like micas. What accounts for their unusual physical properties?
The chemical bonds between the sheets is so weak that very low stresses can allow slip between the sheets; hence, the greasy feel and low hardness.
Which of the following is a renewable resource?
A) coal
B) ice
C) helium gas
D) rock salt
ice
Explain why boulders are not a mineral?
They do not have a well-defined chemical composition
Atoms of the same element, zinc for example, have the same number of ________.
protons in the nucleus
When electrons are shared amongst all atoms, the resulting bond is a(n) ________ bond.
metallic
The criterion for defining something as a mineral?
What is naturally occurring, inorganic, & orderly crystalline structure
Element 20, Ca, has what chemical property?
It behaves as a metal ion, giving up two electrons to form a +2 ion.
What does the tendency of micas to produce thin cleavage flakes suggest about its crystal structure?
The atoms are arranged in orderly arrangements that form strongly bonded sheets separated by weak bonds between the sheets.
Quartz has a characteristic conchoidal fracture, yet rock shops often sell quartz as elongate six sided objects with a pointed termination. What causes this shape?
The planar faces that form the object are crystal faces that grow when the crystals grew into a void.
Which of the following minerals is a silicate?
A) hematite
B) feldspar
C) calcite
D) halite
Feldspar
Which two elements combine to make most of the common rock forming minerals in the crust?
silicon and oxygen
Which common mineral is composed entirely of silicon and oxygen?
quartz
What kind of time span is required to produce most mineral deposits?
tens of thousands to millions of years
Definition of rocks vs. minerals
In a mineral the constituent atoms are bonded in a regular, repetitive, internal structure; a rock is a lithified or consolidated aggregate of different mineral grains.
An atom's mass number is 13 and its atomic number is 6. How many neutrons are in its nucleus?
What is 7?
Using the Table of Elements, elements 17 (Cl) and 9 (F) ________.
are chemically similar because they lie directly below each other on the periodic table
The strong tendency of certain minerals to break along smooth, parallel planes is known as ________.
cleavage
The bond between sodium (Na) and Chlorine (Cl) to form halite (salt) is a(n) ________ bond.
ionic
Wood floats in water, 1 gram is defined as the mass of 1 cubic centimeter of water, a cubic centimeter of quartz weighs ~2.65 g and a cubic centimeter of galena weighs about 7.5 g. The density of these materials from highest to lowest is ________.
galena, quartz, water, wood
Although it is relatively common, limestone is an economically important rock type because its major constituent mineral, ________, is used in the production of ________.
calcite, cement
Clay is an example of ________.
a silicate that forms from weathering of other silicates (Igneous Rocks)
The most common group of rock forming minerals is ________.
the silicates
Joe Geologist discovers a vein made up primarily of quartz but also containing significant amounts of pyrite as well as chalcopyrite. He knows better than to fall for fool's gold, and decides to ignore the vein. Did he make the right decision? Explain.
No, although the pyrite has no value the chalcopyrite has copper and sulfide minerals in quartz veins are a common association with gold bearing veins. He should have examined this in much more detail.
Deposits of which of the following minerals would never be considered an ore?
A) galena
B) hematite
C) chalcophyrite
D) quartz
quartz
Which physical properties are generally used to identify most minerals?
A) luster
B) cleavage
C) hardness
Why do the minerals calcite and dolomite bubble with the mineral or its powder are placed in hydrochloric acid?
A) The acid reacts with the mineral to release CO2 gas that is bound into the crystal as carbonate ion.
The acid reacts with the mineral to release CO2 gas that is bound into the crystal as carbonate ion.
Geologists may choose to lick a mineral to identify it. What 2 minerals is the geologist expecting with this test?
NaCl (halite) or KCl (sylvite)
What describes the light reflecting and transmission characteristics of a mineral?
luster
Why do the minerals calcite and dolomite bubble with the mineral or its powder are placed in hydrochloric acid?
The acid reacts with the mineral to release CO2 gas that is bound into the crystal as carbonate ion.
When a mineral fractures along a cleavage plane, what does this suggest about the crystal structure of the mineral?
The crystal structure contains planes along which chemical bonding is much weaker than other directions.
A cubic centimeter of quartz, olivine, and gold weighs 2.5, 3.0, and 19.8 grams, respectively. This indicates that ________.
gold has a higher density and specific gravity than quartz and olivine
Sulfates always include ________.
SO4-2
Dolomite is a magnesium-rich member of the ________ group.
carbonate
What theory dramatically improved geologist's ability to predict where certain ore deposits were formed?
plate tectonics
In the late 20th century most metal prices were very low but metal prices increased dramatically in the early 21st century. Simultaneously, the early 21st century saw extensive "brown fields exploration" in which companies went to old mining areas and extracted old mine wastes or reopened old mine workings. What is the primary explanation for this activity?
The increase of metal prices made mineral resources that were previously uneconomic into ores that could potentially be extracted profitably.