Silicate Minerals (II)

Question 1

Also known as sheet silicates.

Answer 1

Phyllosilicates

Question 2

Parallel sheets of silica tetrahedra with Si₂O₅, hydrated with water or hydroxyl groups attached.

Answer 2

Phyllosilicates

Question 3

Distinguishing characteristics of Phyllosilicates

Answer 3

1-Direction Basal Cleavage Planes

Question 4

Texture that is found on mica minerals which indicates radiation damage through the decomposition of Zircons.

Answer 4

Bird’s Eye Texture

Question 5

A phyllosilicate mineral which alters from mica minerals.

Answer 5

Clay Minerals

Question 6

A clay mineral that can be seen as green under plane polars.

Answer 6

Chlorite

Question 7

A phyllosilicate mineral that alters from olivines.

Answer 7

Serpentine

Question 8

Fibrous serpentine variety.

Answer 8

Chrysotile

Question 9

Net-like variety of serpentine that exhibits undulose extinction.

Answer 9

Lizardite

Question 10

Scaly or Micaceous variety of serpentine.

Answer 10

Antigorite

Question 11

Three fine-grained varieties of serpentine that may appear like Chlorite.

Answer 11

Greenalite, Berthierite, and Amesite

Question 12

A phyllosilicate mineral that can sometimes be confused with sericite and muscovite, which has varying habits, colorless in PPL, 3rd degree yellow in XPL, and has low to moderate relief.

Answer 12

Talc

Question 13

Also known as framework silica tetrahedra.

Answer 13

Tectosilicates

Question 14

three-dimensional framework of silicate tetrahedra with SiO2 in a 1:2 ratio

Answer 14

Tectosilicates

Question 15

Most common type of twinning observed in Plagioclase Feldspars.

Answer 15

Albite twinning

Question 16

Kind of twinning that can be observed in Alkali Feldspars such as Orthoclase and Sanidine.

Answer 16

Carlsbad Twinning

Question 17

Kind of twinning that are usually observed in Alkali Feldspars such as Microcline.

Answer 17

Tartan Twinning

Question 18

A texture that can be observed when carlsbad twinning plus exsolution lamella is present.

Answer 18

Perthitic Texture

Question 19

Generally, when the extinction angle of the Plagioclase is higher, it means that the Anorthite content is ________.

Answer 19

Higher

Question 20

Kind of zoning where the core is calcic and the rim is sodic.

Answer 20

Normal Zoning

Question 21

Kind of zoning where the extinction angle of the core is larger.

Answer 21

Normal Zoning

Question 22

Kind of zoning where the core is sodic and the rim is calcic.

Answer 22

Reverse Zoning

Question 23

Kind of zoning where the extinction angle of the rim is larger than the core.

Answer 23

Reverse zoning

Question 24

Kind of zoning where the alternation between calcic and sodic cores can be observed.

Answer 24

Oscillatory Zoning

Question 25

A plagioclase that exhibits an oscillatory zoning usually has a __________ core to a more __________ rim.

Answer 25

Calcic Core, Sodic Rim

Question 26

The higher the anorthite content indicates that the plagioclase is rich in _______.

Answer 26

Calcium (Ca)

Question 27

A texture that can be observed where the presence of worm-like figures are observed, usually in the intergrowths of Quartz and Plagioclase.

Answer 27

Myrmekitic texture

Question 28

A texture that can be observed in the intergrowths of Quartz and Alkali Feldspars in Hypabyssal Rocks, which indicates rapid cooling in shallower intrusive environments.

Answer 28

Graphic/Granophyric Texture

Question 29

A texture that can be observed when rounded crystals of Alkali Feldspars are significantly bordered by or rimmed by Plagioclase crystals.

Answer 29

Rapakivi Texture

Question 30

Calcium rich end member of the Plagioclase Feldspar series.

Answer 30

Anorthite

Question 31

Sodium-rich end member of the Plagioclase Feldspar series.

Answer 31

Albite

Question 32

Na-rich end member of the Alkali Feldspar series.

Answer 32

Albite

Question 33

K-rich end members of the Alkali feldspar series.

Answer 33

Sanidine, Orthoclase, and Microcline

Question 34

Plagioclase Feldspar member with the: Ca% = 90-100 Na%= 0-10

Answer 34

Anorthite

Question 35

Plagioclase Feldspar member with the: Ca% = 70-90 Na%= 30-10

Answer 35

Bytownite

Question 36

Plagioclase Feldspar member with the: Ca% = 50-70 Na%= 50-30

Answer 36

Labradorite

Question 37

Plagioclase Feldspar member with the: Ca% = 30-50 Na%= 70-50

Answer 37

Andesine

Question 38

Plagioclase Feldspar member with the: Ca% = 10-30 Na%= 90-70

Answer 38

Oligoclase

Question 39

Plagioclase Feldspar member with the: Ca% = 0-10 Na% = 100-90

Answer 39

Albite

Question 40

Generally, microcline and orthoclase has the habit __________.

Answer 40

Anhedral

Question 41

Generally, Sanidine has the habit __________.

Answer 41

Euhedral

Question 42

Tectosilicate mineral that has no distinct characteristic, and often shows undulose extinction.

Answer 42

Quartz

Question 43

Variety of quartz that showcases radiated habit and undulose extinction.

Answer 43

Chalcedony

Question 44

Isometric feldsphatoid mineral that is light blue in color.

Answer 44

Hauyne

Question 45

Isometric feldsphatoid mineral that is bright blue in color.

Answer 45

Lazurite

Question 46

Isometric feldsphatoid mineral that is blue to violet in color.

Answer 46

Sodalite

Question 47

Hexagonal feldsphatoid mineral that is considered rare.

Answer 47

Cancrinite

Question 48

Tetragonal Feldsphatoid mineral that has low birefringence.

Answer 48

Leucite

Question 49

Hexagonal feldsphatoid mineral that is green in color.

Answer 49

Nepheline

Question 50

True or False Plagioclase feldspars can have perthitic twinning.

Answer 50

False

Question 51

True or False Chlorite has an anomalous interference color of Prussian Blue.

Answer 51

False

Question 52

The visible but fine-grained variety of muscovite is called _____________.

Answer 52

Sericite

Question 53

Microcline is an ___________ Feldspar

Answer 53

Potassium/Alkali

Question 54

Which of the following is NOT a general characteristic of the tectosilicates? non-pleochroic low relief no cleavage low birefringence

Answer 54

No cleavage