POLARIZING MICROSCOPE TECHNIQUES AND APPLICATIONS Flashcards
1
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Used extensively to examine transparent minerals, fragments, grains and small crystals, as well as thin sections of minerals, rocks and other crystalline aggregates
A
Polarizing Microscope
2
Q
useful in the determination of the optical properties of individual crystals or aggregates and in the interpretations of textures, structures, growth patterns, and various relationship of natural or artificial substance.
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Polarizing Microscope
3
Q
source of light of the microscope
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Light source
4
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Concentrates light
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Collector lens system
5
Q
controls light ray bundle at
the source field
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Field iris diaphragm with
field iris diaphragm ring
6
Q
Approximates daylight
note that they only use blue filter before bc the light is yellow
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Filter mount with blue
filter
7
Q
used to polarize the light in one direction
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Polarizer
8
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It controls and illuminates light coming from the source field directed to the object field.
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Condenser
9
Q
controls cone of light catering the objective
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Aperture Iris Diaphragm
10
Q
It is useful for R. I. determination
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Aperture Iris Diaphragm
11
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platform for specimen
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Stage
12
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Fix specimen on stage
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Stage Clips
13
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Used for point locations and systematic traverse in a species along mutually perpendicular directions
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Mechanical Stage
14
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Part of the microscope that we
move left to right.
based on discussion
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Mechanical Stage
15
Q
the amount of space between the front of the objective and the top of the coverglass, when the specimen is in focus
definition is from google but it was discussed
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Free working distance
16
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For Focusing Image (moving in cm)
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Coarse Adjustment Knob
17
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For Focusing Image (moving in mm)
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Fine Adjustment Knob
18
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holds objectives
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Revolving Nosepiece
19
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Essential lenses of microscope for magnification and resolution
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Objectives initial
20
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Magnifications of the Objectives initial
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4x, 10x, 20x, 40x
21
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for insertion of microscopic
accessory plate
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Test plate
22
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polarizes light
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Analyzer
23
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for observing interference
figure
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Bertrand lens
24
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Holds the eye piece
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Observation tube
25
essential lenses of microscope for magnification or resolution conform with objectives
Eyepieces with cross hair
26
for focusing eyepieces
Diopter adjustment ring
27
for camera attachment in
photomicrography
Photo Tube
28
cut to such thickness that it increases or decreases retardation of a section by about 1/4λ (sodium light)
mica plate
29
used to **determine fast and slow directions (electric vectors) of light polarization **in crystals under view on the microscope stage by increasing or decreasing retardation of the light
Gypsum plate
30
ground to produce interference colors from the
beginning of the first to the end of the third or fourth order.
quartz wedge
31
quartz wedge equals to?
0.009
32
Beam of** light consists of a stream of minute particles, or photons,** given off at high velocity by a luminous body that travel through space in straight lines and eventually reach the eye.
Corpuscular Theory
33
The (Dutch) scientist that advanced the Wave Theory
Christian Huygens
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light to be transmitted by the vibration of particle in the waves
Wave Theory
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The phenomena of light such as reflection, refraction, diffraction and interference may be readily explained in accordance with this theory
Wave Theory
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He proposed the Electromagnetic Theory in 1873
James Clerk Maxwell
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considers light as made up of waves but said that waves are electromagnetic
Electromagnetic Theory
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A wave consists of rapidly alternating electric and magnetic fields normal to each other and normal to the direction of propagation of light
Electromagnetic Theory
39
Assuming that radiating oscillators in a black body radiate energy discontinuously in units called quanta.
Quantum Theory
40
He proposed the Quantum Theory
Planck / Max Planck
41
The **locus of all the points** of a medium which receives light wave disturbance simultaneously so that all points are in the same phase.
Wave Front
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A **perpendicular** drawn to the surface of a wave front at any direction of propagation of light
Wave Normal
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Direction in which the light is propagated
Ray of Light
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It is alway perpendicular to wave front
Ray of Light
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Wave front always carries light energy in a direction ____________ to its surface
perpendicular
46
A wave normal represents a _________________
Ray of Light
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The wave normal and direction of propagation of light rays are** perpendicular to the wave front.**
Isotropic
48
The light rays are** not parallel to the wave front.**
Anisotropic
49
May represent a curve combining movement around a circle with motion along a straight line.
Displacement
50
Lies in the wavefront and is perpendicular to the ray in isotropic media.
Vibration direction
51
In ____________, Vibration direction is only perpendicular in limited directions.
anisotropic media
52
Distance between two successive crests or troughs, or any corresponding distance along the wave.
Wavelength
53
Surface determined at a given instant by all parts of a system of waves traveling along the same direction and in the same phase.
Wavefront
54
wavefront is perpendicular only in certain directions in?
anisotropic
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Direction perpendicular to the wave front
Wave Normal
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In _________________ the wave normal and ray direction are the same
Isotropic
57
In ______________, they differ aside from certain directions
anisotropic
58
number of vibrations in a given unit of time.
Frequency
59
maximum displacement of a wave from the line of transmission
Amplitude
60
time interval necessary for a wave to undergo a complete oscillation
Period
61
point of the wave with the maximum upward displacement
Crest
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point of the wave with the greatest downward displacement
Trough
63
a group of light waves following along a sample path
Beam
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straight-line path followed by light in moving from one point to another
Ray
65
equal to the ratio of the wave-normal velocity in a vacuum to the wave-normal velocity in the medium whether isotropic or anisotropic
Refractive index
66
light of a single wavelength
Monochromatic light
67
lies parallel to the plane of the wavefront.
Light vector
68
In ____________ , Light Vector is perpendicular to the direction of the propagation
isotropic
69
In ______________ , Light vector is still
parallel but not perpendicular to the direction of the propagation.
anisotropic
70
2 Types of Vector
1. electric
2. magnetic
71
measures the electrical displacement
electric
72
measures the magnetic displacement or induction.
magnetic
73
Speed of light
186,284 miles per second
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combination of all the different wavelengths visible to the eye
White light
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realistic virtual image with a flat field
Orthoscopic observation
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Setting of Orthoscopic Observation Plane Polarized Light (Uncrossed Nicols)
1. Low to high magnification objective
2. Analyzer Out
3. Condenser top lens out
4. Bertrand lens out
77
Setting of Orthoscopic Observation (Crossed Nicols)
1. Low to High magnification objective
2. Analyzer In
3. Condenser top lens out
4. Bertrand Lens out
78
yields interference figures which represent
an optical pattern caused by the behavior of light in individual crystal
Conoscopic observation
79
Setting of Conoscopic Observation
1. High Magnification Objective (40x)
2. Analyzer in
3. Condenser top lens in
4. Bertrand lens in
5. Accessories in
80
In sample preparation when cutting using the cutting machine it should be at least ___________ size
1''x 2''
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In sample preparation when grinding the size should be
240 mesh abrasive to 800 mesh
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In Heating in sample preparation both ________________________ put Canada Balsam in thin section and heat it for about 30 minutes
the thin section and the sample in a hot plate
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In Heating in sample preparation both the thin section and the sample in a hot plate put ______________ in thin section and heat it for about 30 minutes
Canada Balsam
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In Heating in sample preparation both the thin section and the sample in a hot plate put Canada Balsam in thin section and heat it for about ________________
30 minutes
85
In sample preparation when the sample is put in thin section it is called
Mounting
86
Can be used in Cutting in sample prep
Diamond saw cutter
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Sample can also be grind in a ________________________
300 mesh abrasive up to at least 0.03 mm thickness
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Cover the thin section with the sample using the ______________
Cover Slip
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Clean the thin section using the ________________
xylol solution
90
Study of the interaction of light with minerals
Optical Mineralogy
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Opaque minerals commonly studied in reflected light
ore microscopy
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general application of optical mineralogy is?
to aid in the identification of minerals, either in rock thin sections or individual mineral grains
93
It has Low power objective (10x) and Bertrand lens is optional
Orthoscopic (Uncrossed)
94
Properties that can be observed in Orthoscopic
[] Color and Pleochroism
Cleavage
Shape and Form
Relief/ Refractive Index (R.I.
95
observed w/ plane prolonged light; not always the same as megacopic color
Color
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change in color of a mineral in varying degrees as the stage is rotated due to differences in light absorption & extraordinary rays generally expressed as a formula
Pleochroism
97
The ability of a mineral to separate into smaller
particles bounded of faces of possible crystal form.
Cleavage
98
Cleavage is expressed or best explained in terms of __________
direction
99
qualities of cleavage
[] Perfect
Good
Poor
None
100
Directions of Cleavage
One Direction
Two Directions
Three Directions
Four Directions
Six Directions
All Directions
101
can be expressed by using the terms
euhedral subhedral anhedra
Shape and Form
102
Grains that show no recognizable crystal form
anhedral
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Grains that show imperfect but recognizable
crystal form
subhedral
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Grains that show sharp and clear crystal form
euhedral
105
degree of visibility of a transparent mineral in an immersion medium
Relief
106
A function of the difference n mineral and n medium
Relief
107
R.I of Canada balsam
1.53
108
index of refraction (R.I) of the mineral is Higher than the medium
High Relief
109
R.I of the mineral is lower than the medium
Low Relief
110
almost the same with the medium
Zero Relief
111
varies as the stage is rotated, takes place if one n mineral is near n balsam, and the other n mineral
Change of Relief
112
the contrast between a mineral and its
surroundings due to difference in refractive index.
Relief
113
Relief is __________ when the grain has higher refractive index than surroundings
positive
114
Relief is __________ when the grain has lower refractive index than surroundings
negative
115
Strong negative relief is limited mostly to _____________ like fluorite
non-silicates
116
ratio of the velocity of light in a vacuum to its
velocity in the medium
Refractive Index
117
R.I. constant velocity in all directions
isotropic/ isotropic substances
118
more than one R.I, light velocities vary with direction
anisotropic
119
a band or rim of light visible along a grain/crystal boundary in plane-polarized light.
Becke line
120
It is best seen using the intermediate power lens (or low power in some cases), on the edge of the grain, with the diaphragm stopped down a bit
Becke line
121
If the refractive index is higher than the mounting medium the rays converge towards the ___________ of the grain
Center
122
If the refractive index is lower, the rays diverge towards the ______________ of the grain
Edge
123
In using Becke line to determine the relief: make sure the polars on the microscope are (1)_________ and you have (2)____________ light
1. Uncrossed
2. Plane-polarized light
124
In using Becke line to determine the relief:
Pick a grain that has _________ along the edge of the thin section
sharp edges
125
In using Becke line to determine the relief:
Focus on _____________ power on the edge of the grain
medium power (or lower in some cases)
126
In using Becke line to determine the relief:
Shut the ____________ down a bit
Diaphragm
127
In using Becke line to determine the relief:
Slowly, slightly ____________ the distance between the thin section and the objective
increase (defocus by lowering the stage)
128
In using Becke line to determine the relief:
You will see 2 thin lines appear along the grain boundary which are?
1. Bright or white Becke line
2. Dark Becke line
129
If n grain approximately equals the balsam the bright and dark Becke lines are ______________
colored
130
Observation of transparent Minerals: Orthoscopic (Crossed)
1. Isotropism & Anisotropism
2. Interference Colors
3. Birefringence
4. Twinning
131
Those w/ uniform physical properties in all directions. It remain dark in all positions even if the stage is rotated.
Isotropism
132
Those that display colors in varying degrees as the stage is rotated. It produces interference colors.
Anisotropism
133
For anisotropic minerals only. It is observed w/ reference to the color chart (Michel – Levy Chart)
Interference colors
134
Vary with the thickness of section, nature of mineral; direction in which the mineral section is cut and the light employed
Interference Colors
135
Colors displayed by a birefringent mineral in crossed polarized light
Interference Colors
136
Interference Color
Retardation: 0
Order: _____
Color: Black
zero
137
Interference Color
Retardation: 0 - 5500
Order: _________
Color/s: ______________
Notes: Neutral Colors are cold, yellow dull
Order: First
Colors: Gray, white, Yellow, Red
138
Interference Color
Retardation: ________________
Order: Second
Color/s: _______________
Notes: Purest colors, though not totally pure
Retardation: 5500 - 11000
Color/s: Violet through Spectrum to Red
139
Interference Color
Retardation: __________________
Order: __________________
Color/s: Violet through Spectrum to Red
Note: Have a "fluorescent" appearance
Retardation: 11000 - 16500
Order: Third
140
Interference Color
Retardation: 16500 and up
Order: Fourth and Higher
Colors: ________________________
Note: Colors become more washed out with increasing retardation
Mostly Greens and Pinks
141
The term used in describing interference colors.
Order
142
This maximum colour is often diagnostic of an anisotropic mineral
Birefringence
143
display simultaneously the maximum and minimum refractive indices.
Birefringence
144
**Formation of rational symmetry intergrowth** of 2 or more grains of crystalline species.
Twinning
145
Form of penetration twinning where two
crystals form as penetration twins.
Carlsbad Twining
146
**common within the plagioclase feldspars,** in places where **two adjoining twin slabs or lamellae are mutually reversed** with respect to each other and every alternate twin 'plate' or 'slab' has an identical atomic structure
Lamellar Twining
147
**shows two kinds of repeated twinning** in thin section, with one set of twins arranged at 90° to the other set.
Cross-hatched twinning
148
Refers to solid solution which do not have uniform composition.
Zoning
149
Types of Zoning
Normal Zoning
Reverse Zoning
Oscillatory Zoning
150
Types of Zoning where the center is more calcic becoming more sodic toward the margin
Normal Zoning
151
Types of Zoning where the center is more sodic becoming more calcic toward the margin.
Reverse Zoning
152
Types of Zoning that is normally steplike progressions for more calcic interior to more sodic margins w/ local reversals in adjacent zones
Oscillatory Zoning
153
it is when a mineral becomes dark parallel to the crosshairs.
Parallel Extinction
154
Extinct at an angle
with the direction of polars
Inclined/Oblique
155
planes of mineral to the diagonal; vibration direction is diagonal
Symmetrical
156
Observation of Transparent Minerals: Conoscopic to get interference figure
1. High Power Objective (40x)
2. Condenser top lens in
3. Analyzer In (Crossed Polars)
4. Bertrand lens in
5. Accessories In (Gypsum Plate)
157
Information from Interference Figure
1. Number of Optic Axis
2. Optic Sign (positive or negative)
3. Optic Angle (2v)
4. Dispersion
158
Uniaxial interference Figure
Two arms of the cross form the ____________
Isogyres
159
Uniaxial Interference Figure
Interference Colors, identical to those on the color chart, increases in order from the Melatope cutwards
Isochromes
160
Uniaxial Interference Figure
The point where the Isogyres cross is where the optic axis emerges in the interference figure
Melatope
161
Solution: Alizarine Red S
Mineral: Calcite
Color: ____________
Pink Orange
162
Solution: Alizarine Red S
Mineral: Aragonite
Color: ____________
Pink Orange
163
Solution: Alizarine Red S
Mineral: Witherite
Color: __________
Red
164
Solution: Alizarine Red S
Mineral: Cerussite
Color: __________
Mauve
165
Solution: Trypan Blue
Mineral: Calcite
Color: __________
Dark Blue
166
Solution: Trypan Blue
Mineral: Dolomite
Color: __________
Pale Blue
167
Solution: Silver Chromate
Mineral: Calcite
Color: __________
Red Brown
168
Solution: Silver Chromate
Mineral: Aragonite
Color: __________
Red Brown
169
Solution: Copper Nitrate
Mineral: Calcite
Color: __________
Green/ Bluish Green
170
Solution: Cobalt Nitrate
Mineral: Aragonite
Color: __________
Lilac-Purple
171
Solution: Harris Hematoxillin Solution
Mineral: Calcite
Color: __________
Lilac
172
Solution: Meigen
Mineral: Aragonite
Color: __________
Purple
173
Solution: Meigen
Mineral: Calcite
Color: __________
No Change
174
Solution: Rhodizonic Acid
Mineral: Witherite
Color: __________
Orange/Red
175
Solution: Rhodizonic Acid
Mineral: Calcite
Color: __________
No Change
176
Solution: Tropaeolin
Mineral: Smithsonite
Color: __________
Yellow
177
Solution: Tropaeolin
Mineral: Magnesite
Color: __________
No Change
178
Solution: Hydrogen Peroxide - Potassium Hydroxide
Mineral: Ankerite
Color: __________
Orange
179
Solution: Hydrogen Peroxide - Potassium Hydroxide
Mineral: Siderite
Color: __________
Brown
180
Solution: Lemberg Hydroxide
Mineral: Calcite
Color: __________
Pale Brown
181
Solution: Benzidene
Mineral: Rhodochrosite
Color: __________
Blue
182
Solution: Potassium Ferricyanide
Mineral: Anhydrite / Gypsum
Color: __________
Yellow
183
Solution: Potassium Ferricyanide
Mineral: Rhodochrosite
Color: __________
Pale Brown
184
Solution: Potassium Ferricyanide
Mineral: Dolomite
Color: __________
Blue
185
Solution: Organic Dye Titan Yellow
Mineral: Dolomite
Color: __________
Dark Orange Red
186
Solution: Organic Dye Eosin Y
Mineral: Dolomite
Color: __________
Dark Pink
187
Solution: Organic Dye Congo Red
Mineral: Dolomite
Color: __________
Red
188
Solution: Organic Dye Alizarine Red
Mineral: Dolomite
Color: __________
Lilac
189
Solution: Feigl Solution
Mineral: Aragonite
Color: __________
Black
190
Solution: Sodium Cobaltinitrite
Mineral: K-felds
Color: __________
Yellow
191
Solution: Sodium Cobaltinitrite
Mineral: Plagioclase (Except Albite)
Color: __________
Red
192
Solution: Kirchberg
Mineral: Ankerite
Color: __________
Gray to Black
193
Solution: Kirchberg
Mineral: Siderite
Color: __________
little coloring
194
Solution: Magneson
Mineral: Smithsonite (removed after washing)
Color: __________
Slightly Blue
195
Solution: Magneson
Mineral: Magnesite (Steps after washing)
Color: __________
Dark Blue
196
The identification or interpretation of framework mineralogy and textures leading to classification of wallrock as sedimentary, metamorphic or igneous
Petrography
197
Identification of replacement mineralogy and paragenesis and interepretation in terms of histories of diagenesis, metamorphism, hydrothermal alteration and/or weathering
Petrography
198
refers to degree of crystallinity, grain size or granularity, and the fabric or geometrical relationship between the constituents of a rock.
Texture
199
what are the Degree of crystallinity
Holocrystalline
Holohyaline
Hypocrystalline/Merocrystalline
200
consist wholly of crystals
Holocrystalline
201
consist entirely of glass
Holohyaline
202
Contain both crystals and glass
Hypocrystalline/Merocrystalline
203
Extremely minute, incipient crystals, provided they are birefringent.
Microlites
204
Smaller, spherical, rod- and hair-like isotropic from.
Crystallite
205
Fine Grained
Aphanitic or Eucrystalline
206
Coarse Grained
Phaneritic or Dyscrystalline
207
Very-fine and undistinguishable under petrographic microscope
Cryptocrystalline
208
Very-coarsed grained
Pegmatitic
209
Crystals were bounded completely by crystal faces.
Euhedral / Idiomorphic / Automorphic
210
Crystals were not bounded by crystal faces.
Anhedral / Allotriomorphic / Xenomorphic
211
Crystals were partially bounded by crystal faces
Subhedral / Hypidiomorphic
212
Chiefly minerals are anhedral.
and are common in aplites
Allotriomorphic Granular/ Xenomorphic Granular/ Aplitic / Sugary/ Saccharoidal
213
chiefly minerals are euhedral and are common in dark hypabyssal rocks or lamprophyres
Panidiomorphic Granular/ Automorphic Granular / Lamprophyric
214
all faces are present
Hypidiomorphic Granular/ Hypautomorphic Granular/ Granitic
215
When one mineral is surrounded by another mineral, the enclosing mineral is the _______________
younger
216
Early crystals are generally ___________ or at least more nearly than those of later crystals
Euhedral
217
If both large and small crystals occur together, the ________ one are the first to develop
larger
218
phenocrysts lie in a matrix of glass.
Vitrophyric Texture
219
the groundmass is a dense intergrowth of quartz and feldspar.
Felsophyric Texture
220
the groundmass of feldspar are **rectangular in form** instead of slender lath crystals
Orthopyric Texture
221
**porpyritic texture in which phenocrysts are clustered into aggregates** called glomerocrysts or crystal clots. It is **common** and often included **plagioclase and pyroxenes in basic rocks.**
Glomeroporphyritic Texture
222
Process where accumulation of crystals occur by surface tension and fixing by interpretation due to crystal growth
Synneusis
223
an important consideration in crystal fractionation by crystal settling
Glomerocrysts
224
Refers to crystals, typically phenocrysts, in an igneous rock which contain small grains of other minerals.
Poikilitic Texture
225
A variant the Poikilitic texture, is one where **random plagioclase laths are enclosed by pyroxene or olivine**.
Ophitic Texture
226
A variant the Poikilitic texture,** plagioclase is larger and encloses the ferromagnesian minerals.**
Sub-ophitic
227
**Angular interstice**s between feldspars filled with glass instead of pyroxene
Hyalophitic Texture
228
A genetic term for **a border of secondary minerals** formed at the margin of a primary grain in an igneous or metamorphic rock.
Corona Texture/ Reaction Rim /
Opacitic Rim
229
Secondary rim/coronas
Kelyphitic Rim
230
a textural term indicating that** a crystal occupies the angular space between at least two larger crystals.**
Intergranular Texture
231
A textural term used to denote that the **angular spaces** between larger crystals is **occupied by glass, or glass and small crystals.**
Intersertal Texture
232
Texture of the groundmass of a holocrystalline igneous rock in which** lath-shaped microlites (typically plagioclase) are arranged in a glass-free mesostasis** and are** generally interwoven in irregular unoriented fashion**.
Pilotaxitic Texture
233
A texture of extrusive rocks in which the **groundmass contains little volcanic glass and consists predominantly of minute tabular crystals**, namely, sanidine microlites.
Trachytic Texture
234
An **intergrowth of branching rods of quartz set in a single crystal of plagioclas**e, neighboring rod of quartz have the same lattice orientation and extinguish together.
Myrmekitic Texture
235
________________ commonly exhibits a variety of disequilibrium textures in volcanic rocks, especially in orogeny andesites
Plagioclase
236
common in plagioclase or in pyroxene crystals in extrusive volcanic rocks and is interpreted as the result of mixing processes
Sieve Texture
237
A process by which a solid solution phase unmixes into two separate phases in the solid
state.
Exsolution
238
an intimate intergrowth of sodic and potassic feldspar resulting from subsolidus exsolution
Perthitic Texture
239
an intergrowth arising due to exsolution where potassic feldspar is present as blebs or lamellae within a sodic feldspar.
Anti-PerthicTexture
