Atoms of which elements form the silica tetrahedron, and in which proportion (i.e., how many atoms of each element)?
1 atom of silica (Si);
4 atoms of oxygen (O)
What are the 4 different silicate structures discussed in class?
isolated;
chain;
sheet;
framework
What type of silicate structure does the mineral quartz have?
Framework
What type of silicate structure does the mineral (group) feldspar have?
Framework
What is the Mohs scale used for?
to measure hardness of minerals.
List three minerals that belong to the mineral group of silicates
Possible Answers:clay minerals;
micas (biotite or muscovite);
quartz;
olivine;
garnet;
feldspar (K-feldspar or Na feldspar);
plagioclase;
pyroxenes (augite);
amphibole (hornblende);
List at least 2 minerals that belong to the mineral group native elements.
Possible Answers:diamond (carbon);
graphite (carbon);
gold;
copper;
silver.
List at least one mineral that belongs to the mineral group oxide.
Possible Answers:magnetite;
hematite;
limonite.
List at least one mineral that belongs to the mineral group carbonates.
Possible Answers:calcite;
dolomite.
Define streak of a mineral.
It is the color of the powder that is left when the sample is scratched on an unglazed porcelain plate (streak plate).
A substance that cannot be broken down into other substances by ordinary chemical methods is a(n)
a. crystal
b. element
c. molecule
d. compound
b. element
What is the difference and/or relationship between silicon, silicon-oxygen tetrahedron, silica, and silicate?
Silicon is an element.
Silicon-oxygen tetrahedronis a molecule made up of the element silicon combined with oxygen, in the ratio of 1 silicon atoms and 4 oxygen atoms.
Silica
is the name often given to the silicon-oxygen tetrahedron
Silicate refers to the family of minerals that contain the silicon-oxygen tetrahedron(aka silica) within their atomic structure.
What is the distinction between cleavage and external crystal form?
Cleavage refers to (internal) planar directions along which a mineral tend to break. These directions are directions- or planes- of weakness within the crystalline structure of the atoms forming the mineral.
External crystal form refers to (external) planar surfaces displayed by some minerals as they crystallize (or "grow").
Both cleavage and external crystal form are a reflection of the internal atomic structure of the mineral.
What are the three most common elements (by approximate percentage) in the Earth’s crust?
1- Oxygen (60%).
2- Silicon (20%).
3- Aluminum (6%).
The subatomic particle that contributes mass and a single positive electrical charge is the
A. proton
Atoms of an element containing different numbers of neutrons but the same number of protons are called
D. isotopes
Atoms with either a positive or negative charge are called
a. compounds
b. ions
c. elements
d. isotopes
b. ions
The bonding between Cl and Na in halite is
C. ionic
What are some characteristics of a single silicon-oxygen tetrahedron?
a. The atoms of the tetrahedron are strongly bonded together.
b. It has a net negative charge.
c. The formula is SiO4.
d. It has one silicon atom and four oxygen atoms
Which is not a type of silicate structure?
C. pentagonal
Which of these common minerals is not a silicate?
a. quartz
b. calcite
c. pyroxene
d. feldspar
e. biotite
b. calcite
On the Mohs' scale, what is the hardness of each of these objects:
-Fingernail
-Penny
-Nail
-Glass
-Streak Plate
-Fingernail: 2.5
-Penny: 3.5
-Nail: 4.5
-Glass: 5.5
-Streak Plate: 6.5
The ability of a mineral to break along preferred directions is called
a. fracture
b. crystal form
c. hardness
d. cleavage
d. cleavage
Striations are associated with
D. plagioclase
What are striations?
extremely straight parallel lines on a mineral
Which mineral feels soapy?
Talc
Which mineral tastes salty?
Halite
What color streak does hematite have?
Red
In the lab, what is main diagnostic property used to identify the mineral gypsum?
It is very soft - can be scratched with your fingernail (which means it has a hardness of less than 2.5 on the mohs scale)
List the name of the mineral in the lab which you identified as having a single clearly defined cleavage plane?
mica (biotite and/or muscovite will be accepted too)
Compare feldspar and quartz.
a. How do they differ chemically?
b. What type of silicate structure does each have?
c. How would you distinguish between them on the basis of cleavage''
a) Quartz is pure silica (SiO2), while Feldspar is silica with ions of Ca, Al, Na or K in between silica tetrahedra.
b) Both are framework silicates.
c) Feldspar has 2 distinct angles of cleavage (2 directions at 90 degrees) while Quartz does not (though quartz does have conchoidal fracturing).
Author
herfi001
ID
189943
Card Set
Engineering Geology - Chapter 2 - Atoms, Elements, and Minerals
Description
CHAPTER 2: Atoms, Elements, and Minerals TOPICS: Minerals & Rocks, Atoms & Elements, Ions & Bonding, Crystalline Structures, Silicon-Oxygen Tetrahedron, Nonsilicate Minerals, Variations in Mineral Structures and Compositions, Physical Properties of Minerals, Many Conditions of Mineral Formation
