This presentation is about Mica and Its various Types. I have prepared this presentation during my Bachelor studies. This will help people who want to learn and find out more about Mica and its Types. Thank you for watching..

3. • Sheath/Phyllosilicates
• Mica
• Dioctahedral and Trioctahedral
Sub types
Muscovite
Paragonite
Glauconite
Margarite

4. • Sheath silicates are built up of regular or
irregular sequences of tetrahedral (SiO4)
• Each Si-O tetrahedral group share three
oxygen with each other
• Extend in two dimension that is why they are
called sheath silicates.
• General formula (Si2O5)
• Mica , clay minerals and serphenites are
examples.

5. Mica is the name given to a group of silicate
minerals that have Silicon and Oxygen as their
two major components.
Mica is a metamorphic mineral. Mica formations
are associated with volcanoes and hydrothermal
vents(A hole for the escape of gas or air)

6. • Color
white, yellowish, green, gray.
Streak
colorless
Luster
vitreous to pearly
Hardness(Mohs)
2.5-3

7. • Crystal system
Monoclinic
Cleavage
Perfect
Fracture
Uneven

8. • Mica is widely distributed and occur in
igneous, metamorphic and sedimentary
regimes.
• Large crystals of mica are typically mined from
granitic pegmatite.
• Mica mineral are major rock forming minerals
found in gniess, schist and granites.

9. • Muscovite is the most common mineral of the
mica family.
• Muscovite sheets have a pearly to vitreous
luster on their surface.
• If they are held up to the light, they are
transparent and nearly colorless, but most
have a slight brown, yellow, green or rose-
color tint.

10. • Chemical composition
KAL2(Si3ALO10)(OH)2
color
When splits into thin sheets Muscovite is
colorless, sometimes with a tint of brown,
yellow, green or rose.
Streak
White

11. • Luster
pearly to vitreous.
Cleavage
Perfect.
Crystal system
Monoclinic.

12. Colorless in thin section
No pleochroism
Biaxial <->
Birefringence is high
Extinction is present to cleavage in all
orientations.
Elongation is present

13. Muscovite has a widespread occurrence and is
characteristic of sedimentary, igneous and
metamorphic rocks.
Sedimentary rocks
Sediments eroded from igneous and
metamorphic rocks often carry muscovite,
accounting for its presence in sedimentary
rocks.

14. Igneous rocks
Igneous occurrences include granite,
grandorite, aplite, pegmatites and related
felsic rocks.
Is common in granite and granitic pegmatites.
Muscovite is very common in large variety of
metamorphic rocks including slate, schist,
phyllite, gniess, hornfels and quartzite.

16. • Paragonite is a mineral related to muscovite.
• A basic silicate of sodium and aluminum, a
member of the common mica group.
• Paragonite may have been incorrectly
identified as muscovite. Its weathering is
essentially the same as that of muscovite.

17. Chemical formula is NaAl2(OH]2AlSi3O10
Crystal system is monoclinic
Colorless, pale yellow, grayish, grayish white
and greenish.
Crystal habit is massive or fibrous.
Hardness is 2.5-3
Luster is pearly
Streak is white.

18. Biaxial <->
Surface relief is moderate
Max birefringence is 0.036

19. Paragonite is known definitely to occur in only
a few gneisses, schist and phyllites in which it
appears to play essentially the same role as
muscovite.
Present in fine-grained sediments.

21. Glauconite is green-colored mineral. It is
structurally similar to micas and is sometimes
considered to be one of the mica minerals.
Glauconite is an iron potassium phyllosilicate
mineral of characteristic green color which is
very friable and has very low weathering
resistence.

22. Color is blue green, green, yellow green
Hardness is 2
Monoclinic crystal system
Luster is dull-earthy
Streak is light green

23. Biaxial <->
Birefringence is 0.020-0.032
Pleochroism<X is yellow-green, green and Y, Z
is deeper yellow and bluish green>
 Surface relief is moderate.

24. Glauconite is abundant only in sea floor areas
that are isolated from large supplies of land
derived sediments.
Particles of glauconite are generally sand-sized
or finer.
Glauconite is formed in marine environment.
Some glauconite has been interpreted to have
been formed from pre-existing layered
silicates.

26. Margarite is a calcium rich member of the
mica group of the phyllosilicates with formula
CaAl2<Al2Si2>O10<OH>2

27. Color is grayish, pale pink, yellow, green,
colorless in thin section.
Luster is viterous, pearly
Hardness is 4
Crystal system is monoclinic
Streak is white

28. Biaxial <->
Max birefringence is 0.032
Surface relief is moderate.
Streak is white
Luster is pearly on cleavage and viterous on
lateral faces.

29. It occurs commonly as an alteration product of
corundum, andalusite and other aluminous
minerals.
From low to medium grade metamorphic
rocks, chlorite and mica schist and
glaucophane-bearing rocks.

31. https://www.google.com/search?source=hp&
ei=aQMFXtXQOI2-a-
q3kPAE&q=muscovite&oq=
https://www.google.com/search?q=mica%20s
heet
https://www.sciencedirect.com/topics/earth-
and-planetary-sciences/paragonite