MINERALOGY BASIC CONCEPTS Flashcards
1
Q
Al-Rich modifier
A
Aluminian
2
Q
Ca-Rich modifier
A
Calcian
3
Q
Cr-Rich modifer
A
Chromian
4
Q
Fe2+-Rich
A
Ferroan
5
Q
Fe3+ - Rich
A
Ferrian
6
Q
Mg-rich
A
Magnesia
7
Q
Mn-rich
A
Manganoan
8
Q
how are minerals divided into classes?
A
Depending on dominant Anion or anionic Group
9
Q
Reasons supporting that minerals should be classified based on their anionic group
A
1) minerals having same anion have unmistakable family resemblance which is stronger compared to minerals who share dominant cation; 2) Minerals related by dominan of same anion tend to occur together in the similar geol envi; 3) Such scheme of classification agrees well with current chemical practice in naming and classifying inorganic cmpds
10
Q
Families of minerals are subdivided in terms of what?
A
Chemical Types
11
Q
Groups of minerals in the same family are subdivded in terms of what?
A
Structural similarity
12
Q
General Properties of Sulfides?
A
Majority are ore minerals, opaque, with distinctive colors,and characteristically colored streak
13
Q
Non-Opaque Sulfides with extremely high refractive indices and transmit light only on thin edges?
A
Cinnabar, Realgar, and Orpiment
14
Q
General formula of Sulfides
A
XmZn where X is the metallic while Z is the non metallic sulfide
15
Q
Sulfides that have regular octahedral coordination?
A
Galena (NaCl type)
16
Q
Sulfides that have regular tetrahedral Coordination?
A
Sphalerite
17
Q
- Polymorphs of ZnS
A
Sphalerite and Wurtzite
18
Q
Difference between Sphalerite and Wurtzite
A
Sphalerite have face centered cubic latice (Diamond like) while Wurtzite have hexagonal closest packing
19
Q
- A rare sulfide which is isostructural with sphalerite
A
Greenockite (CdS)
20
Q
The structure of this minerals is derived from Sphalerite by regularly substituting Cu and Fe ions for Zn
A
Chalcopyrite (CuFeS2)
21
Q
The structure of the mineral is based on Sphalerite in which layers of orered Fe and Sn alternate with layers of Cu
A
Stannite (Cu2FeSnS4)
22
Q
This mineral has a combination of Tetrahedral and triangular coordiation?
A
Covellite
23
Q
- What is the difference in terms of occurence with FeS2 polymorphs?
A
Marcasite is said to occur over a range of low to med temp in Sed Rocks and Metalliferous types while Pyrite occurs as magmatic (High T) const.
24
Q
A mineral that has a structure derived from marcasite in which one S per unit formula is replaced by As
A
Arsenopyrite (FeAsS)
25
4. Term used to indicate certain type of unoxidized sulfur mineral that is structurally distinct from a sulfide?
Sulfosalt
26
5. Double sulifides
sulfosalt
27
6. Where do one usually find sulfosalt?
Accessory mineral in Hydr. Vein
28
How many elements are found in native state with the exception of gases in the atmosphere?
20
29
Isostructural members of the gold grp?
Ag, Cu, Pb
30
Isostructral elements with Pt grp
Pd, Os, Ir, Pt
31
Fe rich variety of Ni-Fe
Kamacite
32
Ni rich variety of Ni-Fe?
Taenite
33
What are the two isostructural native semimetals group?
1)As, Sb, and Bi Group and Se,Te Grp
34
Why does gold and silver have complete solid solution and not with copper?
Because Ag and Au have same atomic radii 1.44A
35
Atomic radii of Cu?
1.28A
36
The gold group have unit mesh of?
Face centered cubi lattice
37
Coordination number of Gold group?
12
38
similar properties of the Gold Group?
soft, malleable, ductile and sectile, Conductors, metallic luster and hackly fracture and low melting points
39
Crystal habit and packing of Gold group?
Isometric Hexoctahedral, high densities due to cubic closest packing
40
Common colors of Au,Cu,Ag?
Yellow,Red,White
41
Alloy of platinum and Iridium?
Platiniridium
42
Alloy of iridium and osmium
Iridosmine
43
Members of the Pt group that have hexgonal packing
Palladium, platiniridiu, and Iridosmine
44
Members of the Pt group thta have cubic packing
Platinum and Iridium
45
Difference of Pt group from Au Grp?
Pt grp have higher melting poing and are harder
46
Crystal system of Iron Group
Isometric
47
Members of Fe Group?
Pure Fe, Kamacite and Taenite
48
Radius of Iron atom and Ni atom respectively?
1.26 A and .25 A
49
Ni wt.percent of Fe, Kamacite and Taenite respectively?
5.5 wt% Ni, 27-65 wt%
50
which have closest cubic packing among the members of the Fe Group?
Taenite
51
Chemical bond of Semi metals?
Intermediate bet metallic and covalent
52
do semimetals have stronger bonds than metals?
Yes and its more directional thus having low symmetry (Hexagonal)
53
Common properties of native semi metals?
Weak bond, good cleavage, brittle and poor conductor
54
How is Native sulfur formed?
Sublimation
55
Crystal system of naturally occuring Sulfur?
Ortho
56
temp at which sulfur is stable as ortho
95.5
57
Cyrstal system of a highT sulfur polymorph?
Monoclinic
58
Chemical bonding in sulfur?
Vanderwaals and covalen
59
This element can substitute for Sulfur (1.04A)
Selenium (1.16A)
60
this is the cleavage of diamond caused by the fact that only 34% of the spaces are filled
Octahedral
61
how many neigbor does a carbon in diamond have and its coordination polyhedra?
4, Tetrahedron
62
How many neighbor does a carbon in graphite have and its coordination polyhedra?
3, Triange
63
What gives graphite its relatively high electrical conductivity?
Because 1 of the 4 carbon atoms is free to wander over the suface of the sheet thus creating a dispersed electrical charge
64
How many percent of Ag does California Gold carry?
10-15%
65
How many percent of Ag does electrum carry?
20% or greater
66
How does one express the purity or finesse of gold?
parts per 1000
67
Solid solution of Ag and Hg?
Amalgam
68
SiO ratio of Neso?
1:4
69
Why are nesosilicates have usually equidimensional habit and generally no cleavage?
Because SiO4 tetraheda are independent/Isolated
70
Most abundant mineral in the UPPER MANTLE?
Olivine
71
What's the effect of dense atomic packing to Nesosilicates?
High G
72
Calcic Olivine CaMgSiO4?
Monticellite
73
Gem quality of Olivine
Peridote
74
Garnets are common in what rocks?
Metamorphic
75
Whats the structural formula of Garnets?
A3B2(SiO4)3
76
What types of cations occupy each sites of A and B?
A site - large divalent cations (+2 Fe, Ca,Mg,Mn)
B site - smaller trivalent cations (+3 Al, Fe, Cr)
77
Garnet group in which Al occupies the divalent site?
Pyralspite
78
Ca occupies trivalent site of this Garnet group
Ugrandite
79
Aluminum rich garnet?
Pyrope, Almandine, Spessartine and Grossular
80
Ferrous Garnet
Andradite
81
Chrome Garnet
Uvarovite
82
Black Garnet with Ti and Na?
Melanite
83
Garnet found in Mantle Perioditie and Kimberlites
Pyrope
84
Plymorphs of Al2SiO5?
Kyanite HP, Andalusite LP, Sillimanite HT
85
In which rrocks do these aluminosilicates usually form?
Med-to High grade Met Rocks
86
Which of the three is triclinic?
Kyanite
87
What's the Si O ratio of Sorosilicates?
2:7
88
What is the crystal system of the Epidite Group?
Monoclinic
89
Zoisite has a crystal system of?
Orthorhombic
90
A sorosilicates rich in REEs and Fe2+?
Allanite
91
How many oxygen is shared?
1
92
SiO ratio of ring silcates?
1:3
93
How many oxygen is shared?
2
94
What are the three possible configuration of Cyclosilicates?
Si3O9 (Triangular Ring 3 Silica Tetrahedra)
Si4O12 (Square Ring 4 Silica tetrahedra)
Si6O18 (Hexagonal Ring 6 silica tetrahedra)
95
Example of Si3O9 (Triangular Ring Configuration)?
Benitoite (BaTiSi3O9)
96
Example of Si4O12?
Axinite (Ca,Fe,Mn)3 Al2 (BO3) (Si4O12) (OH)
Papagoite (Ca2Cu2Al2Si4O12(OH6))
97
This is the most basic framework of the structure of common cyclosilicates
Si6O18
98
High Temp polymorph of Cordierite?
Indialite
99
How many oxygens are shared by single chain silicates?
2
100
Whats the Si:O ratio?
1:3
101
How many oxygen are shaed by band form silicates/double chain?
3 on the other half and 2 on the other half
102
SiO ratio of amphibols?
4:11
103
In terms of chemical composition, contrast pyx from amph
amph has OH which means it is hydrous and thus have lighter density and lower refractive index
104
In terms of habit how do they differ?
Amphiboles are long slender crystals usually acicular while pyroxene are stout prisms
105
In terms of crystallization?
In Bowens, pyx crystallizes first than amphibole, if pyx reacts with water at lower temp amphibole may form
106
In terms of prograde and retrograde met, which crystallizes first?
Since prograde met, temperature is increasing, amphbole will crystallize first then pyroxene. For retrograde, pyx first.
107
What is the general formula for pyx?
XY(Si2O6)
108
Cations which can occupy X (Octahedral to Cubic)?
Na, Ca, Mn, Fe2+, Mg, Li
109
Cations which can occupy Y (Normal Octahedral)?
Fe2+, Mg, Fe3+, Al3+, Cr, Ti4+
110
aside from Si4+ what other cation can occupy Z?
Al3+
111
Whats the contrast between X and Y cations
X must be larger in terms of ionic radii
112
This represents the end members of the pyx trapezium SS series
Diopside-Hedenbergite
Enstatite and Ferrosilite
113
What are sodium containing pyx?
Aegirine and Jadeite
114
This represents a SS series of intermediate composition
Aergirine-Augite
115
What represents SS Series between jadeite and Augite?
Omphacite
116
This is a rare pyx fund in Li-rich pegmatites
Spodumene
117
minerals with pyrixene silica ratio but are not structurally identical with pyx
Pyroxenoids
118
How do pyroxenoids differ for pyroxenes?
They have splintery clevages and fibrous habit
119
What s the general formula for amph?
W0-1 X2Y5 Si8O22 (F,OH)2
120
Only ions which can occupy W site?
Na and K
121
Ions which can occupy X site larger cations?
Ca, Na, Mn, Fe, Mg, Li
122
Ions which can occupy Y site?
Mn, Fe, Mg, Fe3+, Al and Ti
123
Z site ions
Si and Al
124
Basal series of amphibole?
Antophyllite-Grunerite
125
Upper calcic series of amphibole?
Tremolite-ferriactinolite
126
Mg rich member of the tremolite-ferractinolite series?
Actinolite
127
What series does Hornblende occur?
Tremolite-ferroactinolite
128
These are the Na-rich amphiboles?
Glaucophane
Riebeckite
Arfvedsonite
129
This is the terms used to described combined structures related to biotite, Pyroxene and amphibole?
Biopyriboles
130
Examples of biopyriboles?
Jimthompsonite, and chesterite
131
What does the greek word phyllon mean?
leaf
132
General habit of phyllosilicates?
Flaky or platy
133
What is the general cleavage for phyllosilicates?
1
134
Other distinguishing characteristics of Phyllosils?
generally soft,
low G, and
may show flexibility or even elasticity
135
How many oxygen of the tetrahedron are shared in an infinetly extended sheet?
3
136
Si:O ratio?
2:5 (T-O)or 4:10 (T-O-T)
137
A sheet in which oxygen or OH group is surrounded by three cations?
Trioctahedral
138
Example of mineral with Trioctahedral Sheet?
Brucite
139
A sheet in which each oxygen or OH group is surrounded only by two cations?
Dioctahedral
140
Example of dioctahedral minerals?
Gibbsite and Corundum
141
Magnesium Octahedral Sites
Brucite
142
Aluminum Octahedral Sites
Gibbsite
143
Properties of T-O layering?
only one side of the octahedral is bonded, Electrically neutral, bonded by Vande Waals
144
Joining tetrahedral sheets on both of the ochatedral sheet?
T-O-T layers
145
Characteristics of TOT minerals
very weakly bonded, which exhibits easy gliding and greasy feel
146
If an univalent cation substitute for every fourth Si what would be the structure?
T-O-T interlayer univalent cation bond
147
properties of a T-O-T interlayered cation bond?
bond is more firm, glding diminished, hardness is increased and slipper feel is lost
148
group which represent T-O-T interlayer cation bond?
True Mica Group (AlSi3O10)
149
Dioctahedral micas with univalent interlayer cation K?
Muscovite
150
Dioctahedral T-O-T + Na interlayer cation?
Paragonite
151
Trioctahedral T-O-T + K interlayer cation?
Phlogopite
152
What are the usual divalent cations that bind TOT?
Ca2+ and Ba2+
153
Properties of TOT with divalent interlayer cation bbond
ionically bonded, cleavage is diminished, hardness and density is increased and flexibility is almost lost
154
What group represent TOT interlayer with divalent cation?
Brittle Mica Group (Al2Si2O10)
155
Trioctahedral TOT divalent cation bond
Clintonite
156
dioctahedral TOT divalent catiion bond?
Margarite
157
How are vermiculute minerals formed?
Talc structure interlaminated by water moelcules in definite sheets
158
This group is derived from the pyrophyllite structure by insertion of sheets of molecular water containing exhangeable cations between pyrophyllite tot layers
Smectite group (montmorillonite)
159
Why are vermiculite and montmorillonite called swelling clays?
Because of their ability to incorporate large amounts of interlayer water
160
K-rich mineral intermediate between Montmorillonite and true micas and are called alkali deficient micas?
Illite
161
These minerals are formed by bending of the tetrahedral sheet to better fit with the adjoining octahedral brucite sheets
Serpentine Mienrals
162
The bending in this serpentine mineral is not continuous but rather corrugrations?
Antigorite
163
The bending in this serpentine mineral is continouous and results to cylindrical tubes
Chrysotile (Fibrous)
164
What is polytypism
A type of polymorphsm wherein different polymorphs exist in different domain of same crystal that have something to do with the way individual layers are stacked
165
Charge of framework silicates?
Neutral
166
How much of the crust is made up of tectosilicares?
64%
167
What is the Si O ratio of tectosiliicates?
1:2
168
How many oxygens are shared?
4
169
What is synthetic polymorph of quartz?
Keatite
170
Only polymorph of quartz with Si in octahedral coordination with Ox?
Stishovite
171
What does a lower specific gravity and refractive index imply?
Higher temperature forms with great lattice energy (beta)
172
A high silica glass of variable composition
lechatelierite
173
A silica with locally ordered sphere sturctures and highly variable H2O content which is the main composition of microscopic shells of Diatoms and Radiolaria
Opal
174
In which oxide is Stishovite isostructural?
Rutile
175
Most dense Silica Polymorph which exists in High Pressure (>75Kbar (7.5 Gpa, 250 km) found in the deep mantle?
Stishovite
176
A dense high temp high pressure silica polymorph (20Kbar, 2GPa)
Coesite
177
This is where stishovite and coesite were both naturally indentified
Meteor Crater, Arizona
178
High Temp Low Pressure silica which is common in silica-rich volcanic rocks
Triydmite and Cristobalite
179
What are the principal naturally occuring SiO2 Polymorphs?
Low/alpha quartz, Low/alpha tridymite, and low/alpha cristobalite
180
Naturally occuring SiO2 that has the lowest symmetry and the most compact?
low quartz (alpha)
181
Naturally occuring SiO2 that has the high symmetry and the a more open structure?
low tridymite (alpha)
182
Naturally occuring SiO2 that has the highest symmetry and the most expaned structure?
low cristobalite (alpha)
183
Why is there no naturally occurring beta quartz?
Because high quartz are stable only at temp greater than 580 deg celsius, at atm conditions, it transforms to Alpha quartz
184
Which of the displacive polymorphic pairs have low symmetry?
Low variety or the alpha
185
Whats the effect of increased in pressure in polymorphic transformation?
It increases inversion temperature
186
Examples of Barium Felspars?
Celsian (BaAl2Si2O8)
Hyalophane (K,Ba)(Al,Si)2 Si2O8
187
What is the cleavage of feldspars?
2 direction close to 90
188
General Hardnesss of Feldspars?
6
189
Sp. Gravity of felds?
2.55-2.76
190
Whats the variation in Al-Si distribution in feldspar crystals relative on rate of cooling at high?
Those that are cooled rapidly have disordered Al-Si distrbution
191
Bakit AlSi3O8?
Kasi dapat SiO2 or Si4O8 since Al is incorporated one Si site will be given to Al
192
High temp polymorph of kFelds?
Sanidine
193
Low temp polymorph of Kfelds?
Microcline
194
Arrange Kfelds in terms of orderness of Al-Si Distribution
Sanidine - Orthoclase - Microcline
195
Arrange Kfelds in terms of Temp formation from highest to lowest
Sanidiine - Orthoclase - Microcline
196
What parameters can u use to differentiate polymorphs of K-felds
Unit cell dimension, 2V or extinction Angle
197
Where do you usually find microcline based on its temp of formation?
Deep seated rocks and pegmatites
198
Where do one usually find orthoclase?
Intrusive rocks formed at intermediate temo
199
Where does one usually find sanidine?
High Temp silic lava extrusive
200
What specific varieties of feldspars are involved in perthitic texture?
Microcline and Albite
201
Thin layers of albite in a host of K-felds
Perthite
202
in what temp conditions does solid solution bet plagioclases occur?
High Temp
203
What are the 3 exsolution texture that may occur in Plagioclase?
1) Peristerite 2)Boggild Intergrowth/Labradoresence and 3)Huttenlocher intergrowths
204
How can one detect the exosolution textures in plag series?
Through Iridiscence
205
Exsolution or intergrowth which occur at An2 - An15
Peristerite (Gem stone variety
206
intergrowth at An47 to An 58?
Boggild Intergrowth/Labradorescence
207
Intergrowth at An 60 to An 85
Huttenlocher intergrowths
208
These are anhydrous framework silicates similar to feldspar but has much lower silica content
Feldspathoids
209
What are the chracteristics of feldpathoid melts?
Alkaline (rich in K, Na, Ca) and less silicic
210
This is the deifining character of feldspathoid structure
Large sturctural cavities which make them open for more anions
211
G range of feldspathoids
2.15-2.5
212
Feldspathoid with Cl
Sodalite
213
Feldspathoid with Carbonate with yellow rose colors ?
Cancrinite
214
Feldspathoid with SO4?
Noselite
215
Feldspathoid with SO4, Cl amd S?
Lazurite
216
Zeolite normally form as
Amygdules
217
These are hydrous framework aluminoslicates?
Zeolites
218
anions in zeolites?
Na, Ca, K and H2O
219
What is itumesence?
A swelling up which results when water is expelled during heating
220
Whats the literal meaning of Zeolite from their greek etymolgy?
Boil Stone
221
in what metamorhic conditions are zeolite found?
Low grade regional met zone (Zeolite facies)
222
Hardnes of zeolite?
3.5-5.5
223
G of Zeolite?
2.0-2.4
224
Main divisions of zeolites?
1) Fibrous habit (Chain Structure) 2)Platy Habit with (Sheet structure) and 3)Equant Habit (Framework structure)
225
Due to the ability of being rehydrated, where do zeolites usually used in industry?
Dessicants (removal of water in petroleum)
226
This is a silicate which demonstrates molecular shieveing
Zeolites
227
Contrast Hard and Soft Water?
Hard is Ca-rich while Soft is Na-rich
228
which property of zeolite makes it suitable for removing harmful ions in radioactive waste , or ammonia from sewage and agricultural waste
Cation exhange property
229
Common Uses of Zeolite
1) Removal of radioactive isotopes from nuclear waste water
2) Scrubbing of pollutants from stacks
3)Sewage Treatment, water softening (Removal of Ca)
230
Shared properties of Zeolites?
Diaphaneity (Transulcent to Transparent)
Luster (Vitreus to Peary)
SG (2.1-2.3)
Streak (White)
Hardness (Intermediate 3.5-5.5)
231
metamorphic minerals with compositions suggestive of feldspars
Scapolite
232
Intermediate member of Marialite-Meionite SS?
wenerite
233
which has affinity to albite?
Marialite
234
which has affinity to anorthite?
Meionite
235
Groups of strongly bonded anionic complexes which are always stronger than those occuring between other ions of the structure
Anisodesmic
236
which mineral groups are anisodesmic
carbonates , Nitrates, Phosphates, Chromates, Tungstates, Arsenates, Vanadates, Molybdates
237
Mineral group that is mesodesmic
Borates
238
what is the polyhedra formed by anionic PO4, VO4 and AsO4 group with oxygen?
Tetrahedra
239
Common phosphates
Apatite, Monazite (Th)
240
Where do Monazite usually occurs?
in Beach deposits with other heavy resistant mienrals
241
Phosphate minerals found in pegmatites and source of lithium
Amblygonite
242
Arsenates that is similar in structure with vanadinite and Pyromorphite
Mimetite
243
What is the coordination polyhedra of BO3?
Triangular
244
Regarded as a network former in glass manufcature and is used in the preparation of special glasses of light weight and high transparencey to energetic radiation
Boron
245
EV of borates
1
246
EV of sulfates
1.5
247
what type of bonds occur in the sulfate anion?
Covalent
248
Most important and common of the anhydrous sulfates?
barite group
249
how many ox ion is coordinated with barium ion?
12
250
How many ox ion is coordinated in anyhdrite?
8
251
Most important and abundant hydrous sulfate?
Gypsum
252
what is the effect of reconstructive transformation of gypsum to anyhdrite?
Decrease in specific volume and loss of perfect cleavage
253
This group contains compounds of fairly small divalent cations in 6 coordination with moO
Wolframite Grp
254
This group contains compounds of larger cations in 8-coordination w/ WO4, and MoO4
Scheelite Grp
255
What are the two partial series betwee W and Mo
1) Scheelite (CaWO4) - Powellite (CaMoO4); 2)Stolzite (PbWO4) and Wulfenite (PbMoO4)
256
Element used to manufacture hard, refractory steel alloys used for hig speed cutting tools, incadescent lamps, electrical contacts, crucibles and spark plugs
Tungsten
257
What is the ev of CO3?
1 1/3
258
What is the residual ev of oxygens in CO3?
2/3
259
What is the coordination polyhedra of Carbonates?
Triangle
260
Why do carbonates fizz?
Because with the addition of Hydrogen ion from the acid, carbonate becomes unstable and breaks down to yield CO2 and H2O
261
Space group of calcite
R 3bar c
262
what is the structure of calcite?
Rhombohedral
263
What is the cleavage of calcite?
Rhombohedral
264
What is the miller indicices assigned to such cleavage?
101bar1
265
how many Ca to O coordination does calcite have?
6
266
How many Ca to O coordination does aragonite have?
9
267
what are the ionic radii of cations in aragonite group?
>1.0A
268
What crystal system does aragonite have?
Orthorhombic
269
space group of aragonite
Pmcn
270
Stable form of CaCO3 at room temp
Calcite
271
BaCa(CO3)2
Barytocalcite
272
CaMn(CO3)2
Kutnahorite
273
Temperatures at which calcite and dolomite is at solid soluton
1000-1100 deg cel
274
Between Calcite Grp and Aragonite GRp, which is bonded to much larger cations?
Aragonite:Large Cations
275
Members of Hydroxycarbonates?
Azurite
Malachite
276
What is the coordination polyhedra of Nitrates?
Triangle
277
E.v of nitrates
1 2/3
278
What are the ion dominant in halides?
Electronegative Halogen ions (Cl.F.Br,I) (Class VIIA or Row 17)
279
Charge of halogens?
neg1 causing the minerals to be brittle, ttanslucent and quite soluble
280
What is the coordination polyhedra of NaCl?
Octahedral (6)
281
KF?
Carobiite
282
Sulfides that have NaCl-type of structure
Galena (PbS), Alabandite (MnS)
283
Oxide that are isostructural with Halite?
MgO (Periclase)
284
CsCl-structure coordination number and polyhedra?
Cubic (8)
285
structure of XY2 halides?
Cubic (8)
286
bonding of halides?
Pure Ionic Bonding
287
Common properties of Isometric Halides?
Low H
High Melting Point
Poor conductor of heat and electricity in solid state
288
What mechanism allows conduction of electicity in halides?
Electrolysis - transport of charges by ions
289
what will happen if halogens are combined with smaller and more polarizing cations?
Lower symmetry, bonds become covalent and presence of water or hydroxyl ion
290
Halide formed by refining aluminim ores such as bauxite
Cryolite
291
General property of Oxides
Hard, dense, and refractory
292
Where do Oxides occur?
Accessory minerals in ign and met rocks abd as resistant detrital grains in sediments
293
Genreal formula of simple oxides
X2O (Cuprite Grp)
XO (Periclase Grp)
XO2 (Rutile Grp)
X2O3 (Corundum Grp)
294
General formular of multiple oxides
XY2O4 (Spinel Grp)
XYO3 (Perovskite Grp)
XYO2 (Ilmenite Grp)
295
Chief ore of iron
hematite and magnetite
296
Chier ore of chromium
Chromite
297
Chief ore of manganese
Pyrolusite, Manganite, Romanechite
298
Chief ore of tin
Cassiterite
299
Chief ore of Uranium
Uraninite
300
Ore of Titanium
Ilmenite
301
bond type of oxides
Ionic
302
Coordination polyhedra of hematite group
Octahedral (CN 6)
303
Do periclase show cation vacancies?
NO
304
Polymorphs of Rutile
Anatase and
Brookite
305
Why is Rutile prismatic?
It is the reflection of the chainlike arrangement of octahedra
306
CN of pyrolusite, rutile, and cassiterite?
6 octahedral
307
CN of Cerianite, Thorianite and Uraninite?
8 Cubic
308
General formular of Spinel Group
XY2O4 or X8Y16O32
309
Differentiate Normal Spinel and Inverse spinel
Normal have geeral formula of X8Y16O32 while in inverse 8 of the 16 cations occupy the 8 tetrahedral site so that Y (YX) O4
310
What is the expected coordnation polyhedra for magnesium?
Octahedral
311
What is the expected coordination polyhedra for aluminum?
Tetrahedral
312
What led petrologists to suggest that olivine which is thought to be abundant in the mantle, is converted to spinel-type srtuctures at great depths?
Since spinel structure is similar to that of the olivine series and the total cation carge is identical however spinel structure is 12% denser than olivine
313
What are the high pressure olivine polymorphs?
Ringwoodite and Wadsleyite
314
What characterizes members of the Hydroxide group?
Presence of (OH) or H2O milecules which causes the bonds to be weaker than oxides and as lower SG
315
Differentiate brucite and gibbsite in terms of structure
Brucite is trioctahedral while gibbsite is dioctaheral
316
what is the natural crystal form of diaspore?
Boehmite
317
What is the natural crystal form of goethite?
Lepidochrocite
318
Important ore mineral in lateritic soils
Goethite
319
Finely granular, amorphous mixtures of Iron, Hydroxide, and Hydrated iron hydroxide minerals
Limonite
