Mica

About Mica mineral and it's economic importance

1. ECONOMIC GEOLOGY FORMATION AND ECONOMIC IMPORTANCE OF MICA PRESENTED BY M.PREM[TEAM 5]

2. INTRODUCTION India dominated the world market in mica ever since the demand of mica in electrical industry has become indispensable. The world depends on India for quality mica sheets and splitting. The USA, Japan, Germany, Russia, Belgium, Poland, France and Czechoslovakia are principal countries where India is exporting mica. India is the leading producer of sheet mica, while USA is the principal producer of scrap mica.

3. PROPERTIES OF MICA Mica belongs to sheet silicate(phyllosilicate) . All sheet silicates have atomic structures composed of sheets(layers) of tetrahedra with alkalies and other metals between. Possess well developed BASAL cleavage. General formula for micas is So, we can describe most mica compositions in terms of three end members: Muscovite Annite Phlogopite  

4. PHYSICAL PROPERTIES OF MICA Color Purple, rosy, silver, gray (lepidolite) Dark green, brown, black (biotite) Yellowish-brown, green-white (phlogopite) Colorless, transparent (muscovite) Cleavage Perfect Fracture Flaky Mohs scale hardness 2.5–4 (lepidolite) 2.5–3 biotite 2.5–3 phlogopite 2–2.5 muscovite Luster Pearly, vitreous Streak White, colorless Specific gravity 2.8–3.0 Diagnostic features Cleavage

5. TYPES OF MICA MINERAL NAME COMMERCIAL NAME CHEMICAL COMPOSITION MUSCOVITE Potassium mica (White mica, ruby mica) PARAGONITE Sodium mica PHLOGOPITE Magnesium mica (Amber mica) BIOTITE Magnesium-Iron mica (Black mica) LEPIDOLITE Lithium mica ZINWALDITE Lithium-Iron mica (Lithium biotite) Li,Fe,K,F in addition to Al and ROSCOELITE Vanadium mica V,Mg,Fe in addition to Al and MINERAL NAME COMMERCIAL NAME CHEMICAL COMPOSITION MUSCOVITE Potassium mica (White mica, ruby mica) PARAGONITE Sodium mica PHLOGOPITE Magnesium mica (Amber mica) BIOTITE Magnesium-Iron mica (Black mica) LEPIDOLITE Lithium mica ZINWALDITE Lithium-Iron mica (Lithium biotite) ROSCOELITE Vanadium mica

6. MODE OF OCCUERRENCE MINERAL OCCURRENCE MUSCOVITE Silicic pegmatites, mostly with granitic intrusive PHLOGOPITE From quartz free pegmatites BIOTITE From metamorphic rocks-biotite-schists LEPIDOLITE AND ZINWALDITE Restricted to granitic pegmatites The Zoned or Composite pegmatite with a central quartz core, followed by a zone of pegmatite with quartz, felspar, and mica, and a mica zone at the contact of the pegmatite-vein and the country rock.

7. SCHEMATIC STRUCTURE OF THE PEGMATITE

8. ORIGIN Mica has been formed from magmatic solutions in the pegmatite. From an Igneo-aqueous deposit or hydrothermal replacement of earlier minerals. The fluids responsible for the formation of mica-pegmatite, were rich in volatiles ( )and (K, Na, Li, Al and Si). It has been suggested that the formation of pegmatites is favored in a geological setting where the mica-schist, country rock, has metamorphosed under AMPHIBOLITE -facies conditions. The origin of phlogopite mica is different from that of muscovite where the former forms under the action of gases, vapors and aqueous solutions of granitic magma on magnesium rich host rocks, dolomitized limestones and dolomites. Under the action of magma pure limestone re-crystallized into marble, and dolomitized limestones turn into diopside rocks.  

9. GEOLOGICAL DISTRIBUTION OF MICA IN INDIA Mica is widely distributed in India, the minerals bearing Mica is found in the states of  Andhra Pradesh, Maharashtra, Jharkhand, Odisha, Rajasthan, etc. State-wise total resource distribution of Mica is as follows:- Andhra Pradesh leads with 41%  share in the country’s total resources followed by Rajasthan (21%) Odisha (20%) Maharashtra (15%) Bihar (2%) and The remaining 1% is in Jharkhand and Telangana together.

10. Andhra Pradesh:   Andhra Pradesh is the  largest mica producing state of India . In Andhra Pradesh.  Nellore district produces the best quality mica. Vishakhapatnam, West Godavari, and Krishna are other important mica-producing districts. Rajasthan:   Second largest producer. In Rajasthan, the mica belt extends for about 320 kms from Jaipur to Bhilwara and around Udaipur. Bhilwara district located in this belt is the   most imported producer of Mica.

11. Jharkhand:   Third largest producer. Mica is found in a belt extending for about 150 km in length and 32 km in width from the  Gaya district of Bihar to Hazaribagh and Koderma districts of Jharkhand . This Mica belt runs in an  East-West direction . This belt contains the richest deposits of  high-quality   ruby mica . Kodarma (largest reserve of mica in the world), Giridih, and Domchanch are the chief collecting centers  (located in this belt) where Mica is processed. Apart from this  Munger in Bihar  also have sufficient mica deposits. The main centres of mica production in this belt are Kodarma, Dhorhakola, Domchanch, Dhab, Gawan, Tisri, Chakai and Chakapathal.

12. Karnataka:   Mica deposits occur in  Mysuru and Hasan districts  of Karnataka. Tamil Nadu:   In Tamil Nadu,  Coimbatore, Tiruchirappalli, Madurai and Kanyakumari districts. Kerala:   In Kerala, Mica deposits are found in  Alleppey district. Maharashtra:   Ratnagiri in Maharashtra  has rich mica deposits. West Bengal:   Purulia and Bankura in West Bengal  are known for mica deposits.

13. USES OF MICA Mica is a naturally occurring stone that directly applies to a set of minerals containing silica in its highest form. This mineral is mostly used in gypsum wallboard combined compound where it acts as wadding and prevents cracking. There are a variety of uses of this mineral such as: It is used in paints as a pigment extender and also helps to brighten the tone of colored pigments. In the electrical industry the same as thermal insulation, and electrical insulators in electronic equipment. Its shiny and glittery appearance makes it ultimate for toothpaste and cosmetics. The high thermal resistance allows it to be used as an insulator in various electronics. MICA SHIELDS   or  Gauge Glass Mica   can be used to secure the liquid level gauges from corrosive and acidic solutions.