The chlorite group is a group of phyllosilicate minerals composed mainly of magnesium, iron, and aluminum. Chlorite has a monoclinic crystal structure and perfect cleavage. The most common chlorite group members are clinochlore, which is magnesium-rich, chamosite, which is iron-rich, nimite, which is nickel-rich, and pennantite, which is manganese-rich. Chlorite is commonly found in metamorphic rocks and as a secondary mineral formed from the alteration of other minerals in igneous rocks. It has no significant industrial uses but may be present as a constituent of crushed stone.

1. Chlorite group of
mineral

2. CHLORITE GROUP
• Derived from greek word chlorous which
means green.
• The chlorites are a group of
of phyllosilicate minerals.
• Chlorite group devoid alkali metals and rich in
ferrous iron.
• Chlorite mineral are monoclinic crystal system.
• They possess a perfect cleavage.

3. CHLORITE GROUP
 Chemical formula :- (Mg,Fe,Li)6AlSi3O10(OH)8
 Colour :- Green
 Streak :- Green,Brown
 Cleavage :- Perfect
 Fracture :- Flexible
 Hardness :- 2 to 2.5
 Specific Gravity :- 3
 Transparency :- Transparent
Physical properties :-

4. Optical property of Chlorite :-
• Pleochroism :- Yellow- green – brown
• Colour :- Green,greenish brown
• Relief:- Moderate to high
• Birefrenges :- Low
• Interference Colour :- Anomalous blue,1st
order yellow,brown,purple
• Crystal System :- Monoclinic
• Habit :- Chlorite has habit similar to the other
micas;foliated book and individual flakes in a
quartz-feldspar matirx are common

5. Members of the chlorite group :-
Baileychlore (Zn,Fe+2,Al,Mg)6(Al Si)4O10(O,OH)8
Chamosite (Fe , Mg)5Al(Si3Al)O10(OH)8
Clinochlore (Mg,Fe2+)5Al(Si3Al)O10(OH)8
Cookeite LiAl4(Si3Al)O10(OH)8
Donbassite Al2[Al2.33][Si3AlO10](OH)8
Gonyerite (Mn,Mg)5(Fe+3)2Si3O10(OH)8
Nimite (Ni,Mg,Al)6(Si,Al)4O10(OH)8
Odinite (Fe,Mg,Al,Fe,Ti,Mn)2.4(Al,Si)2O5OH4
Orthochamosite (Fe+2,Mg,Fe+3)5Al(Si3Al)O10(O,OH)8
Pennantite (Mn5Al)(Si3Al)O10(OH)8
Ripidolite (Mg,Fe,Al)6(Al,Si)4O10(OH)8
Sudoite Mg2(Al , Fe)3Si3AlO10(OH)

6. MOST COMMON MEMBER OF
CHLORITE GROUP :-
 Clinoclore ( Magnesiun (Mg)-rich chlorite)
 Chamosite (Iron (Fe)-rich chlorite)
 Nimite (Nickel (Ni) -rich chlorite)
 Pennantite (Manganese (Mn) -rich chlorite)

7. CLINOCHLORE
• Clinochlore is a member of the Chlorite group and is
one of the better-known members. It most often is an
uninteresting matrix for more important minerals, but
the rare and beautiful pink to red variety. Kammererite
is very popular and treasured by collectors.
Clinochlore forms a series with the Chamosite within
the Chlorite group. Chamosite is the iron rich end
member, and Clinochlore is the magnesium-rich end
member. Their properties are very similar, and they are
difficult to distinguish from each other, though
Clinochlore is softer, lighter, and usually more
transparent than Chamosite

8. Physical property of Clinochlore
• Chemical formula :- (Mg5Al)(AlSi3)O10(OH)8
• Colour :- Pink red purple yellow grey brown
• Streak :- White
• Cleavage:- Perfect
• Fracture :- Uneven
• Crystal System :- Monoclinic
• Hardness :- 2-2.5
• Specific Gravity :- 2.5-3
• Lusture :- Vitreous to pearly
• Transparency :- Transparent to translucent

9. Image of Clinochlore
Foliate Clinochlore Sheet

10. CHAMOSITE
• Chamosite is a member of the Chlorite, and it
forms a series with the mineral Clinochlore
• Chamosite is the iron rich end member, and
Clinochlore is the magnesium-rich end
member.
• Their properties are very similar, and they are
difficult to distinguish from each other, though
Chamosite is harder, heavier, and usually less
transparent than Clinochlore.

11. Physical property of Chamosite :-
• Chemical formula :- (Fe,Mg)5Al(Si3Al)O10(OH)8
• Colour :- Greenish-grey , grey, greenish-black
• Streak :-White
• Cleavage :- Perfect
• Fracture :- Uneven
• Hardness :- 2.5-3
• Specific Gravity :- 3-3.4
• Crystal System :- Monoclinic
• Lusture :- Vitreous to pearly
• Transparency :-Translucent

12. Image of Chamosite

13. NIMITE

14. Physical property of Nimite :-
• Chemical formula :-(Ni,Mg,Al)6(Si,Al)4O10(OH)8
• Colour :- Yellow green
• Streak :-White
• Cleavage :- Perfect
• Fracture :- Uneven
• Hardness :- 3
• Specific Gravity :- 3-3.4
• Crystal System :- Monoclinic
• Lusture :- Vitreous to pearly
• Transparency :-Translucent

15. Pennantite

16. Physical property of Pennantite :-
• Chemical formula :- (Mn5Al)(Si3Al)O10(OH)8
• Colour :- Red,brown, dark -green,black
• Cleavage :- Perfect
• Fracture :- Uneven
• Hardness :- 2-2.5
• Specific Gravity :- 3-3.4
• Crystal System :- Monoclinic
• Lusture :- Vitreous to pearly
• Transparency :-Translucent

17. OCCURRENCE :-
• Chlorite is a common mineral in low grade
metamorphic rocks, such as chlorite schist.
• In igneous rock, chloriteis mostly a secondary
mineral,forming from the hydrothermal
breakdown of pyroxene,amphibole and
boitite.
• Chlorites are common in argillaceous
sedimentary rocks, where they occur with clay
minerals.

18. Uses of Chlorite
• Chlorite is a mineral with a low potential for
industrial use.
• It does not have physical properties that make it
suited for a particular use, and it does not contain
constituents that make it a target of mining.
• When found, chlorite is usually intimately
intermixed with other minerals, and the cost of
separation would be high.
• Chlorite is not mined and processed for any
specific use. Its major use is as a coincidental
constituents in crushed stone.

19. Distinguishing from other minerals
• Chlorite is so soft that it can be scratched by a
finger nail. The powder generated by
scratching is green. It feels oily when rubbed
between the fingers.
• The plates are flexible, but not elastic like
mica.

20. Reference :-
• Rutley’s elements of mineralogy.
• Internet

21. Thanks for your
attention…