Why Mica is used in electrical and scientific instruments?

Mica is an important mineral. It is a bad conductor of heat and electricity and is, therefore, used in electrical and scientific instruments. It is hard, clastic and transparent/ transluscent.

That is why it is used in the manufacture of aeroplanes, cars, trucks, etc. Transparent sheets are made by the use of manganese. Medicines and decoration art pieces require mica for their production. It is also used in the manufacture of paper, rubber, paint, etc.

India is the world’s leading producer of sheet mica and accounts for about 60% of the global mica trade. Important mica bearing pegmatite occur in Andhra Pradesh, Jharkhand and Rajasthan.

The tentative recoverable reserves of mica in A.P are 44837 tonnes. Jharkhand 13554 tonnes and Rajasthan 1589 tonnes.

Mica is separated as thin flakes (l/400th cm) from blocks of mica. Good quality mica is found in the shape of blocks. Poor quality mica is found as scrap..In the world 25% of mica is found in the shape of wide block and 75% as scrap.

Mica is found in mainly three colours- black, white and green. Mica is of different varieties like muscovite or Potash mica, biotite, Phlogoplite, and lepidolite. The first two varieties are of large economic value.

White mica is obtained from Pegmatite (Igneous rock). Ruby mica is the best while mica with a little rosy colour is called biotic mica. Distribution of Mica in India

In India Mica is found in three belts:

(1) Bihar , Jharkhand Belt.

This belt produces quality mica. In India it is called Bengal Ruby. It is used in manufacturing electrical and electronic instruments.

This belt covers an area of 100 X 22 square km. Its thickness is upto 30 metres. The main districts are Hazaribagh, Dumke (Santhal Pargana) and Bhagalpur districts of Jharkhand. Besides these, mica is also there in Dhanba, Palamau, Ranchi, Singhbhum districts of Jharkhand state.

Mica is mined in a large number of mines. Gaya and Munger (Monghyr) districts of Bihar are also known for mining of mica. There are a number of mines. The women and children are employed for separating the thin flakes from mica blocks. These are considered to be the most skilled workers in the world for this job.

(2) Andhra Pradesh Belt.

This belt is about 100 km long and 16-25 km wide. It is in the district of Nellore. The important places are Gudur, Atmakur, Kavali and Rapur. It is a semi circular belt. It exploits 30% of mica of India.

There are certain mines in this belt where high grade mica, known as ‘Honey mica’ is mined. Another quality, Ruby mica is mined in a number of districts of Andhra Pradesh like Krishna, Viskhapatnam, Guntur, Chitoor, Anantpur, East and West Godavari.

(3) Rajasthan Belt.

About 15% of country’s mica is produced in Rajasthan. This belt stretches for 320 km from North of Jaipur to South of Bhilwara and around Udaipur. The important deposits are in Ajmer district at Bhinai, Kalinjir, Balad, Ratanpura, Jalia etc.

Bhilwara District:

Danta, Toonka, Partabpura, Ghoras, Baneri and others.

Udaipur District:

Sardargarh, Bhagatpura, Gangapur, Amet etc.

In Bhilwara and Udaipur districts, ruby mica is mined. Elsewhere, spotted mica is found. In the Jaipur and Tonk districts also mica is mined at a number of places.

Karnataka :

In Mysore and Hassan districts.

Orissa :

Ganjam District.

Tamil Nadu :

Tirunelveli, Coimbatore, Tirchunapalli, Madurai, Dharamapuri and Kanya Kumari districts.

Kerala :

Alleppey, Quilon.

Chhattisgarh :

Surguja, Bilaspur, Bastar districts.

M.P. :

Balaghat, Chhindwara, Narsingpur districts.

Maharashtra :

Ratnagiri District.

Assam :

Goalpara District.

West Bengal :

Bankura and Puruliya Districts.

Orissa :

Mayurbhanj and Cuttack Districts.

Mica is a strategic and an indispensable mineral of India, where Industrial development is picking up.

Mica is used in manufacturing a variety of products other than electronics and electricals. Mica bricks are made from waste mica.

India produces nearly 80% of world mica. Mica is a very important export item from India. It is exported to a number of European countries, USA, Canada, China, Japan and Australia.

Export earnings in mica have dwindled on account of invention of artificial mica and emergence of Brazil as a major rival in the world market.