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Questions and Answers
Which anionic unit is represented by the chemical formula $CaWO_4$?
Which anionic unit is represented by the chemical formula $CaWO_4$?
- Carbonates
- Sulfates
- Silicates
- Tungstates (correct)
Approximately what percentage of known minerals are composed of carbonate, oxide, hydroxide, phosphate, sulfide, and native elements?
Approximately what percentage of known minerals are composed of carbonate, oxide, hydroxide, phosphate, sulfide, and native elements?
- 29% (correct)
- 50%
- 75%
- 15%
What is the historical origin of the mineral name 'feldspar'?
What is the historical origin of the mineral name 'feldspar'?
- Derived from a German word describing its presence in tilted fields (correct)
- Named after its locality in Spain
- Derived from Latin, referring to its color
- Related to its use as a waste material in mining
According to the information, what is the role of the Commission on New Minerals, Nomenclature and Classification (CNMNC) in mineral naming?
According to the information, what is the role of the Commission on New Minerals, Nomenclature and Classification (CNMNC) in mineral naming?
Which term is used to describe a mineral that lacks a definite molecular structure, where all directions in the mass are sensibly the same?
Which term is used to describe a mineral that lacks a definite molecular structure, where all directions in the mass are sensibly the same?
What are the smooth plane surfaces that bound a crystal referred to as?
What are the smooth plane surfaces that bound a crystal referred to as?
What does the 'habit' of a crystal describe?
What does the 'habit' of a crystal describe?
In the context of crystal symmetry, what is a 'plane of symmetry'?
In the context of crystal symmetry, what is a 'plane of symmetry'?
What type of symmetry is defined by a revolution that repeats itself two times, resulting in a 180° turn?
What type of symmetry is defined by a revolution that repeats itself two times, resulting in a 180° turn?
Which type of symmetry is associated with crystals that possess neither a plane nor an axis of symmetry, yet may be symmetrical with reference to their center?
Which type of symmetry is associated with crystals that possess neither a plane nor an axis of symmetry, yet may be symmetrical with reference to their center?
How many minerals, approximately, are known according to Klein et al. (2013)?
How many minerals, approximately, are known according to Klein et al. (2013)?
What is the origin of the name 'garnet'?
What is the origin of the name 'garnet'?
Which of the following best defines a crystal?
Which of the following best defines a crystal?
What is meant by molecular structure in the context of minerals?
What is meant by molecular structure in the context of minerals?
A mineral with no external crystalline form is said to be what?
A mineral with no external crystalline form is said to be what?
What is the relationship between the faces or planes on a crystal?
What is the relationship between the faces or planes on a crystal?
About how many minerals are classified as silicates?
About how many minerals are classified as silicates?
What is the classification of minerals that includes ZnS, $FeS_2$, and $CuFeS_2$?
What is the classification of minerals that includes ZnS, $FeS_2$, and $CuFeS_2$?
What is the definition of 'gangue'?
What is the definition of 'gangue'?
How is a 'tetragonal of fourfold' axis of symmetry defined?
How is a 'tetragonal of fourfold' axis of symmetry defined?
Flashcards
Gangue
Gangue
Waste material in an ore deposit.
Spar
Spar
An old mining term for crystals with easily discernible faces and cleavage.
Crystal
Crystal
The general polyhedron form bounded by smooth surfaces; the normal form of a mineral species.
Molecular Structure
Molecular Structure
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Massive
Massive
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Amorphous
Amorphous
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Faces (Crystals)
Faces (Crystals)
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Habit
Habit
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Plane of symmetry
Plane of symmetry
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Axis of symmetry
Axis of symmetry
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Binary of twofold
Binary of twofold
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Trigonal of threefold
Trigonal of threefold
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Tetragonal of fourfold
Tetragonal of fourfold
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Hexagonal of sixfold
Hexagonal of sixfold
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Center of symmetry
Center of symmetry
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Study Notes
- Chemical compositions are based on anionic units
- There are approximately 4150 known minerals
- Silicates make up 1140 of the minerals
- Sulfides and Sulfosalts make up 624 of the minerals
- Phosphates make up 458 of the minerals
- Oxides and Hydroxides make up 411 of the minerals
- Carbonates make up 234 of the minerals
- Native Elements make up 90 of the minerals
- Approximately 29% of minerals are carbonate, oxide, hydroxide, phosphate, sulfide, and native elements
- These represent the most common minerals abundant in rock types
Naming of Minerals
- The naming of minerals, while interesting, is not a scientific process
- Many common mineral names date back to times when scientific tools were unavailable to classify, define, or describe minerals quantitatively
- Quartz: Applied to describe waste material produced during mining
- Feldspar: Derived from the word "feldtspat" in 1740, referring to spar in tilted fields overlying granite bedrock in Sweden
- Garnet: Derived from the Latin word "granatum" for pomegranate, due to its color similarity
- Mineralogists must follow the characterization of newly discovered minerals set by the Commission on New Minerals, Nomenclature and Classification (CNMNC)
- Minerals can be named after their original locality (e.g., aragonite found in Argon, Spain)
- Gangue: Waste material in an ore deposit
- Spar: An old mining term for crystals with discernible faces and easy breakage or cleavage
General Morphology Relations of Crystals
- Crystal: A general polyhedron form bounded by smooth surfaces, assumed by a chemical compound under intermolecular forces when transitioning from liquid or gas to solid
- A crystal is the normal form of a mineral species
- Molecular Structure: This is the arrangement of molecules under the forces exerted during solid formation
- Crystalline: A mineral with a definite molecular structure is crystalline
- Amorphous: Substances lacking a definite molecular structure, with uniform properties in all directions, are amorphous
- External Form: Crystals are bounded by smooth plane surfaces called faces or planes, arranged with symmetry and mathematical laws
- External Forms: Galena, Vesuvianite, Chrysolite
- Diversity of Forms or Habit: Forms of crystals can be diverse, but angles between like faces remain constant
- The habit of minerals can vary indefinitely with the number and size of faces
- Diversity of Size: Crystals can range from microscopic to a yard or more in diameter, with minute crystals being as fully developed as larger ones
Symmetry in General
- Faces of crystals are arranged according to laws of symmetry
- A plane of symmetry is symmetrical with reference to a plane for each face in a "mirror-image" sense
- An axis of symmetry is the solid of revolution through a number of degrees about an axis/line
- Binary of twofold: A revolution of two times which gives a 180°
- Tigonal or threefold: The revolution repeats 3x and forms 120°
- Tetragonal of fourfold: When the revolution repeats itself four times in a complete revolution and forms 90°
- Hexagonal or sixfold the revolution repeats itself six times in a complete revolution and forms 60°
- A center of symmetry: Crystals may be symmetrical with reference to their center even without plane or axis symmetry (e.g., Triclinic crystals)
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