clay mineral description

1. DEPARTMENT OF APPLIED GEOLOGY
DR. HARISINGH GOUR VISHWAVIDYALAYA
SAGAR, M.P
( A CENTRAL UNIVERSITY)
CLAY MINERALS
Under The Guidance Of:- Presented By:-
Dr. G.C. Gautam Lavkush Maurya
Assistant Professor M.Tech 1st Sem.
Dr. H.S.Gour V.V. Sagar Reg.No.- Y18251014

2.  Chemically ,clay minerals are hydrous aluminium phyllosilicates ,sometimes they
occur with variable amounts of calcium,magnesium,iron ,sodium and potassium.
 Clay mineral are usually ultra fine grained normally considered to be less than
2μm in size on standard particle classification.The upper limit of clay size is 4µm.
 Because of size it require special technique for study. These include X-ray
diffraction,electron diffraction and various spectroscopic methods
 Clay is a naturally occurring material composed primarily of fine grained
minerals, which shows plasticity through a variable range of water content and
which can be hardened when dried or fired.
INTRODUCTION

3. CONTENTS
1. INTRODUCTION
2. CHEMICAL COMPOSITION
3. PHYSICAL PROPERTIES
4. OPTICAL PROPERTIES
5. STRUCTURES
6. CLASSIFICATION OF CLAY
1. 1:1 CLAY STRUCTURE
2. 2:1 CLAY STRUCTURE
7. KAOLINITE
1.OCCURRENCE
8. SMECTITE
9. ILLITE
10. VERMICULITE
11. PARAGENESIS
12. USES
13. REFERENCE

4.  SMECTITE GROUP
• DIOCTAHEDRAL SMECTITE(0.5Ca,Na)0.7(Al,Mg,Fe)4(Si,Al)8O20(OH)4.nH2O
• TRIOCTAHEDRAL SMECTITE(0.5Ca,Na)0.7(Al,Mg,Fe)6(Si,Al)8O20(OH)4.nH2O
 ILLITE(K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,H2O]
 VERMICULITE(Mg,Fe,Al)3(Al,Si4)O10(OH)2.4H2O
CHEMICAL COMPOSITION
 KAOLINITE Al2Si2O5(OH)4

5. PHYSICAL PROPERTIES
Property Kaolinite Smectite Illite Vermiculite
colour White-red Yellow,green grey Brown,green
Habbit foliated Lammelar,microcrys
talline
foliated Large crystalline
plates
Lustre Dull or earthy Dull or earthy Dull Greasy
Fracture uneven uneven uneven uneven
Hardness 2-2.5 1-2 1-2 1.5-2
Cleavage perfect perfect perfect perfect
Sp.gravity 2.16-2.68 1.7-2 2.6-2.9 2.4-2.7
Crystal system Monoclinic Monoclinic Monoclinic Monoclinic

6. OPTICAL PROPERTIES
Property Kaolinite Smectite Illite
POLARISATION
COLOUR
Brownish/Reddish Yellow to Green Colourless
HABBIT Massive Earthy Mass ---
OPTIC SIGN Biaxial(-) Biaxial(-) Biaxial(-)

7. STRUCTURES
Clay minerals are made of two distinct structural units
1)Silicon tetrahedron
2)Aluminium octahedron

8. (a)1:1 clay structure
CLASSIFICATION OF CLAY
All clay minerals are made of different combinations of two sheets-tetrahedral sheet and
octahedral sheet.
Ex-kaolinite ,halloysite
O
Al
Si

9. (b)2:1 clay structure
CLASSIFICATION OF CLAY
All clay mineral are made of different combinations of two sheets-tetrahedral sheet and
octahedral sheet.
Ex- montmorillonite, illite and vermiculite
O
Al
Si

10. KAOLINITE
1:1 phyllosilicate mineral(platy shape)
There is no
interlayer swelling
Low cation exchange
capacity
 Kaolinite is a pure, white
firing clay
It also contains
quartz,ilmenite,rutile and
haematite.
Bonding between the layers
are vanderwaals forces and
hydrogen bonding

11. KAOLINE HAND SPECIMEN

12. OCCURRENCE
 Kaolinite are as primary residual deposits formed by weathering or low
temperature hydrothermal alteration of feldspar,muscovite and other Al
rich silicates usually in acid rocks.(granites,rhyolites,quartz,diorite ,etc.)
2KAlSi3O8 +3H20 Al2Si2O5(OH)4+4SiO2+2K(OH)
 In secondary deposits, parent minerals have been transported under
suitable non-alkaline condition and deposited in deltaic,lagoonal or other
non-marine environment.

13.  2:1 Structure
 It is most
expendable of all
place
 Layers are weakly
bounded by weak o-
o bonds or cation
oxygen bond
 High cation exchange
capacitiy
SMECTITE

14. HANDSPECIMEN OF SMECTITE
BEIDELLITE
Hectronite
SAPONITE
NONTRONITE
MONTMORILLONITE

15. ILLITE
 2:1 Structure
 Non-expanding
 Cation-exchange capacity
of illite is smaller than that
of smectite but higher
than that of kaolinite
 Interlayer spacing of
structure are filled by K
cations resulting non-
expanding nature
 It is product of early
alteration of Mica

16. HANDSPECIMEN OF ILLITE

17. VERMICULITE
 2:1 Structure
 Moderate to high expandable
 High cation exchange capacity
 Vermicullite is weathered product of micas in
which K+ ions between molecular sheets are
replaced by Mg+2 and Fe+2 ions

18. HANDSPECIMEN OF VERMICULITE

19. PARAGENESIS
 SMECTITE AND ILLITE: In the burial diagenesis of mudrocks,
increasing depth and temperature facilitate the conversion of di
octahedral smectite to illite, and tri octahedral smectites to chlorite.
 VERMICULLITE: These are formed by alteration of
phlogopite/biotite,chlorite,pyroxene,etc resulting in ultrabasic and
basic rocks.

20. USES
 In ceramics( it is main component of porcelain)
 In paint it is used to extend titanium dioxide white pigment and modify gloss levels
 In cosmetics(pre-work skin protection and barrier creams)
 In paper industry
KAOLINITE
SMECTITE
 In drilling of Water & oils wells
 Stopping leakage
 As lubricant

21. VERMICULITE
 In fireproofing of structural steel and pipes
Exfoliated vermiculite provides a low density material with excellent thermal
and acoustic insulation properties
 In seed germination

22. REFERENCE
 MINERALOGY-DEXTER PERKINS
 INTRODUCTION TO MINERALOGY-WILLIAM
D.NESSE
 AN INTRODUCTION TO ROCK FORMING
MINERALS-J ZUSSMAN
 WWW.SLIDESHARE.COM
 WIKIPIDEIA.org

23. THANK YOU