Clay Minerals

Question 1

Kaolinites

Answer 1

Xx Si2 O5 (OH)4

Pore-filling
books/stacks of hexagonal plates
CEC = 1-10 [milli-equivl/100 gms]

Question 2

Chlorites

Answer 2

(Mg6-y-x Fey Alx) (Si4-x Alx) O10 (OH)8

Pore-lining
Edge-to-face ( ˧ )
CEC = 5-30 [milli-equivl/100 gms]

Question 3

Vermicultites

Answer 3

(Al2 or Mg3) (Si3 Al) O10 (OH)2 Mg0.5 • nH2O

Question 4

Chlorite

Answer 4

(Mg6-y-x Fey Alx) (Si4-x Alx) O10 (OH)8

Question 5

Talc

Answer 5

Mg3 Si4 O10 (OH)2

2:1 layer silicate
trioct

Question 6

Pyrophillite

Answer 6

Al2 Si4 O10 (OH)2

2:1 layer silicate
dioct

Question 7

Montmorillonite

Answer 7

(Al0.7 Mg0.3) Si4 O10 (OH)2 K0.3

Question 8

Saponite

Answer 8

Mg3 (Si3.7 Al0.3) O10 (OH)2 K0.3

Question 9

Beidellite

Answer 9

Al2 (Si3.7 Al0.3) O10 (OH)2 K0.3

Question 10

Illite

Answer 10

Al2 (Si3.2 Al0.8) O10 (OH)2 K0.8

Question 11

Muscovite

Answer 11

Al2 (Si3 Al) O10 (OH)2 K

Question 12

Biotite

Answer 12

(Mg, Fe)3 (Si3 Al) O10 (OH)2 K

Question 13

Paragonite

Answer 13

Al2 (Si3 Al) O10 (OH)2 Na

Question 14

Phlogopite

Answer 14

Mg3 (Si3 Al) O10 (OH)2 K

Question 15

Kaolinite

Answer 15

Al2 Si2 O5 (OH)4

1:1 layer silicate
dioct

Question 16

Antigorite

Answer 16

Mg3 Si2 O5 (OH)4

1:1
trioct

Question 17

Silicon Tetrahedral layer

Answer 17

(Si2 O5)^-2

Question 18

Porosity

Answer 18

Φ = (ρma - ρb) / (ρma - ρf)

ρma = ρg = grain density
ρb = bulk density
ρf = fluid density

Question 19

CEC

Answer 19

= mg of element adsorbed by 100gm clay / equivalent wt of cation

equivl. wt = atomic wt / valence #

Question 20

Units of clay minerals

Answer 20

Si4 O10
Mg (OH)2 (brucite)
Al (OH)3 (gibbsite)

Question 21

Brucite

Answer 21

Mg3 (OH)6

Question 22

Gibbsite

Answer 22

Al2 (OH)6

Question 23

Smectites

Answer 23

Xx (Si3.7 Al0.3) O10 (OH)2 K0.3

Pore-lining
Web-y appearance
Swelling clays
CEC = 80-140 [milli-equivl/100 gms]

Question 24

Illite

Answer 24

Al2 (Si3.2 Al0.8) O10 (OH)2 K0.8

Pore-lining
Whispy/hair-like
CEC = 10-40 [milli-equivl/100 gms]