ESS 101 Laboratory 3A: An Introduction to Minerals
ATTENTION : You must complete this lab BEFORE you complete Laboratory 3B: Mineral
Identification. Lab 3A will teach you about the characteristics we use to describe minerals. Lab 3B
will have you use the characteristics to identify minerals.
If you do not first complete Lab 3A, Lab 3B will be difficult/impossible.
Find a PDF of this lab here.
Learning Goals
By completing this lab, students will learn:
The technical definition of a mineral
The different physical properties of a mineral and how they form
How to use common diagnostic properties to identify a mineral
Introduction
The unique composition and structure of minerals give them each a unique set of physical properties. Minerals
are classified based on these physical properties.
During this lab you will become familiar with the important physical p roperties of minerals and learn how
to identify the common rock-forming minerals. Your ability to determine the physical properties of
minerals by observation and testing is more important than merely being able to recognize and name
minerals. You will be given the opportunity to identify many of these minerals in the future, when we
examine rocks.
Minerals vs. Rocks
A rock is any natural aggregate of minerals, mineraloids, glass, and/or organic particles. For example,
granite is a rock composed of several different minerals, rock salt is a rock composed of a single mineral
(halite), rock opal is a rock composed of the mineraloid opal, obsidian is a rock composed of volcanic glass,
and coal is a rock composed of organic particles. Mineral identification is an important component of
geology because the mineral composition of a given rock can tell us a lot about how and where the rock
formed.
Classification Systems
Classification schemes can be subdivided into two principal types, descriptive and interpretive.
Descriptive schemes are based on observable physical properties, while interpretive schemes imply a
knowledge of how those properties were acquired. We classify minerals based on their physical
properties. These properties rehect the chemical elements and crystalline structure of the mineral.
Therefore, mineral classification is basically descriptive. When we learn about rocks in future
laboratories we will also focus on interpretive classification schemes.
, Physical Properties of Minerals
Because a mineral's physical properties are based on its specific chemical composition and crystalline
structure, these properties are unique to each mineral and can be used for identification. The following is
a discussion of common properties used for mineral identification.
In this week’s two-part lab, you will be learning how to recognize and use diagnostic mineral properties to
identify 14 common rock-forming minerals (Figure 3-2). Each mineral has been assigned a specimen number
for this lab (M1 - M14). In this part of the lab, we will introduce you to specific diagnostic properties that can be
used to help identify minerals. In the next part of the lab, you will be asked to use these diagnostic properties to
identify the 14 minerals.
Figure 3-2. Fourteen common rock-forming minerals (M1 - M14 will be identified in the laboratory this week using their
physical (diagnostic) properties. The diagnostic tools we will use to assist us in this identification are shown on the
bottom of the image.
1 0 points
Laboratory Honor Statement
Cheating or plagiarism of any kind will not be tolerated in ESS 101. This includes copying answers from
a friend or classmate, copying answers verbatim found on the internet or other literary sources, or
copying any work that may answer the question being asked. Make sure you always use your own words
when answering the questions in the homework and cite appropriate references if you use them to help
you answer the question. Anyone caught violating the academic code of conductLinks to an external
site. will be reported to the UW Academic Misconduct representative.
I acknowledge that I have carefully read and understand the above statement regarding the
consequences of cheating and plagiarism, and promise to complete my work in this class with honesty
and integrity. Answer "True" below supporting your acknowledgement.
True
False
, What are Minerals?
Minerals are the basic building blocks that make up the solid Earth. Therefore, any study of the solid
Earth must begin with an understanding of minerals.
A mineral, by definition, is a (1) naturally occurring, (2) solid, (3) usually inorganic element or compound
with a (4) definite crystalline structure and (5) chemical composition which varies only within specific
limits.
Common examples are quartz, diamond, garnet, talc, and halite (salt).
Some useful hints about what a mineral is/isn't:
1. Although compounds produced in a laboratory can have many of the characteristics of a
mineral, they are not naturally occurring and therefore are not minerals.
2. Minerals are solids, therefore liquids and gases are not considered minerals.
3. Nearly all minerals are inorganic, that is, not produced by living organisms.
4. Minerals have a distinct crystalline structure (Figure 3-1). Each mineral has an orderly,
predictable arrangement of atoms. For example, the minerals graphite and diamond are both
made of carbon but what makes them unique is a significant difference in the way the atoms are
arranged (Figure 3-1). (A mineraloid differs from a mineral in that it lacks crystalline structure
(i.e., is amorphous). For example, opal is a mineraloid; it has the same composition as quartz but
lacks the crystal structure.)
5. Minerals have a definite chemical composition that can be expressed as a specific chemical
formula. Quartz, for instance, is composed of silicon and oxygen and has the formula SiO2.
Some minerals have more complex compositions. Garnet's formula, for instance, is
A3B2(SiO4)3, where A and B represent a variety of elements such as Ca, Mg, Fe, and Mn.
Although the exact composition of garnet can vary, the ratio between A and B is constant — 3
atoms of A for every 2 atoms of B.
Figure 3-1. The atomic structure of (a) diamond and (b) graphite. Diagrammatic inserts show bonding relationships of
carbon atoms. In diamond, each carbon atom is strongly bonded (covalent bonds) to four adjacent carbon atoms. In
graphite, each carbon atom is strongly bonded to only three neighboring atoms. Strongly bonded atoms in graphite
occur in sheets, which are only loosely attached to one another by weak van der Waal forces.
ATTENTION : You must complete this lab BEFORE you complete Laboratory 3B: Mineral
Identification. Lab 3A will teach you about the characteristics we use to describe minerals. Lab 3B
will have you use the characteristics to identify minerals.
If you do not first complete Lab 3A, Lab 3B will be difficult/impossible.
Find a PDF of this lab here.
Learning Goals
By completing this lab, students will learn:
The technical definition of a mineral
The different physical properties of a mineral and how they form
How to use common diagnostic properties to identify a mineral
Introduction
The unique composition and structure of minerals give them each a unique set of physical properties. Minerals
are classified based on these physical properties.
During this lab you will become familiar with the important physical p roperties of minerals and learn how
to identify the common rock-forming minerals. Your ability to determine the physical properties of
minerals by observation and testing is more important than merely being able to recognize and name
minerals. You will be given the opportunity to identify many of these minerals in the future, when we
examine rocks.
Minerals vs. Rocks
A rock is any natural aggregate of minerals, mineraloids, glass, and/or organic particles. For example,
granite is a rock composed of several different minerals, rock salt is a rock composed of a single mineral
(halite), rock opal is a rock composed of the mineraloid opal, obsidian is a rock composed of volcanic glass,
and coal is a rock composed of organic particles. Mineral identification is an important component of
geology because the mineral composition of a given rock can tell us a lot about how and where the rock
formed.
Classification Systems
Classification schemes can be subdivided into two principal types, descriptive and interpretive.
Descriptive schemes are based on observable physical properties, while interpretive schemes imply a
knowledge of how those properties were acquired. We classify minerals based on their physical
properties. These properties rehect the chemical elements and crystalline structure of the mineral.
Therefore, mineral classification is basically descriptive. When we learn about rocks in future
laboratories we will also focus on interpretive classification schemes.
, Physical Properties of Minerals
Because a mineral's physical properties are based on its specific chemical composition and crystalline
structure, these properties are unique to each mineral and can be used for identification. The following is
a discussion of common properties used for mineral identification.
In this week’s two-part lab, you will be learning how to recognize and use diagnostic mineral properties to
identify 14 common rock-forming minerals (Figure 3-2). Each mineral has been assigned a specimen number
for this lab (M1 - M14). In this part of the lab, we will introduce you to specific diagnostic properties that can be
used to help identify minerals. In the next part of the lab, you will be asked to use these diagnostic properties to
identify the 14 minerals.
Figure 3-2. Fourteen common rock-forming minerals (M1 - M14 will be identified in the laboratory this week using their
physical (diagnostic) properties. The diagnostic tools we will use to assist us in this identification are shown on the
bottom of the image.
1 0 points
Laboratory Honor Statement
Cheating or plagiarism of any kind will not be tolerated in ESS 101. This includes copying answers from
a friend or classmate, copying answers verbatim found on the internet or other literary sources, or
copying any work that may answer the question being asked. Make sure you always use your own words
when answering the questions in the homework and cite appropriate references if you use them to help
you answer the question. Anyone caught violating the academic code of conductLinks to an external
site. will be reported to the UW Academic Misconduct representative.
I acknowledge that I have carefully read and understand the above statement regarding the
consequences of cheating and plagiarism, and promise to complete my work in this class with honesty
and integrity. Answer "True" below supporting your acknowledgement.
True
False
, What are Minerals?
Minerals are the basic building blocks that make up the solid Earth. Therefore, any study of the solid
Earth must begin with an understanding of minerals.
A mineral, by definition, is a (1) naturally occurring, (2) solid, (3) usually inorganic element or compound
with a (4) definite crystalline structure and (5) chemical composition which varies only within specific
limits.
Common examples are quartz, diamond, garnet, talc, and halite (salt).
Some useful hints about what a mineral is/isn't:
1. Although compounds produced in a laboratory can have many of the characteristics of a
mineral, they are not naturally occurring and therefore are not minerals.
2. Minerals are solids, therefore liquids and gases are not considered minerals.
3. Nearly all minerals are inorganic, that is, not produced by living organisms.
4. Minerals have a distinct crystalline structure (Figure 3-1). Each mineral has an orderly,
predictable arrangement of atoms. For example, the minerals graphite and diamond are both
made of carbon but what makes them unique is a significant difference in the way the atoms are
arranged (Figure 3-1). (A mineraloid differs from a mineral in that it lacks crystalline structure
(i.e., is amorphous). For example, opal is a mineraloid; it has the same composition as quartz but
lacks the crystal structure.)
5. Minerals have a definite chemical composition that can be expressed as a specific chemical
formula. Quartz, for instance, is composed of silicon and oxygen and has the formula SiO2.
Some minerals have more complex compositions. Garnet's formula, for instance, is
A3B2(SiO4)3, where A and B represent a variety of elements such as Ca, Mg, Fe, and Mn.
Although the exact composition of garnet can vary, the ratio between A and B is constant — 3
atoms of A for every 2 atoms of B.
Figure 3-1. The atomic structure of (a) diamond and (b) graphite. Diagrammatic inserts show bonding relationships of
carbon atoms. In diamond, each carbon atom is strongly bonded (covalent bonds) to four adjacent carbon atoms. In
graphite, each carbon atom is strongly bonded to only three neighboring atoms. Strongly bonded atoms in graphite
occur in sheets, which are only loosely attached to one another by weak van der Waal forces.
