Introduction to Minerals and their types

Minerals are solid substances formed due to natural processes that happen on earth. They are made from an inorganic compound with several elements combined. Minerals have a definite chemical composition and a characteristic crystalline structure with atoms arranged in a specific order. Scientists have identified the formation and existence of around 4000 minerals in the earth’s crust. Some of them are very common and have a high value attached to them. At the same time, some others are uncommon and not very valuable. The process of discovery and using them to accelerate human development has been of interest ever since the copper age. Initially, minerals were used to make utensils and tools. With the industrial revolution, mining processes have gained momentum across the world.

Based on their chemical composition, minerals are classified into metallic minerals and non-metallic minerals. 

What are metallic minerals?

Metallic minerals have one or more metallic elements in their composition. They are obtained from igneous rocks and metamorphic rocks. Metallic minerals contain various metals like gold, iron, aluminium, nickel, copper, zinc, lead, etc. Some of them, like iron, copper, and zinc, have become an essential part of our lives. Such metals are extracted from the metallic minerals through mining and smelting.  Metallic minerals are further classified into ferrous minerals and non-ferrous minerals.

1. Ferrous minerals have iron in their metallic content. They function as an important source of iron. 
2. Non-ferrous minerals are those metallic minerals that do not contain iron but have a higher proportion of other minerals like copper. 

What are non-metallic minerals?

Non-metallic minerals do not have any metals in their chemical composition. So, they do not produce metals when melted. Sand, marble, clay, salt, etc., are some examples of nonmetallic minerals. Conversion of these minerals into usable products involves several steps, most of which are energy-intensive – like heating, grinding, crushing, shaping, etc. 

They are further classified into fuel minerals and other non-metallics. 

1. Fuel minerals are those organic minerals like fossil fuels like coal and petroleum, formed from animal and plant remains. 
2. Other non-Metallics include those made from inorganics like limestone, graphite, etc. 

Differences between metallic and non-metallic minerals

Evidently, metallic and non-metallic minerals differ by chemical composition. They also have differences in texture, malleability, appearance, functionality, etc. Some notable differences are as follows –

• Metallic minerals essentially have metals in raw form as their primary chemical composition. Non-metallic minerals do not have metals in their composition
• Metallic minerals are usually found in the cracks and joints of igneous and metamorphic rocks that form large plateaus. Non-metallic minerals are found in the beds or layers of sedimentary rocks in plains and young fold mountains
• Metallic minerals, when melted, produce metals. Non-metallic minerals do not produce metals when melted
• Metallic minerals appear lustrous and shine on their own. Non-metallic minerals are not lustrous
• Metallic minerals are malleable and ductile. They can be drawn into several forms like wires and sheets without breaking. Non-metallic minerals are not malleable. When hammered to be drawn into wires and sheets, they break into pieces. Hence, non-metallic minerals cannot be moulded into wires or sheets
• Metallic minerals like copper are good conductors of heat and electricity. While non-metallic minerals like mica act as insulators and are bad conductors of heat and electricity
• Metallic minerals produce a sound when hit. Hence, they are called sonorous. On the other hand, non-metallic minerals do not produce a sound when hit
• Metallic minerals exist only in the solid-state, while non-metallic minerals exist in all three states of matter-solids, liquids, and gases
• Iron ore, nickel, gold, copper, aluminium, lead, zinc are some examples of metallic minerals. Sand, clay, marble, limestone, gravel, gypsum, dolomite, and quartz are commonly used non-metallic minerals

Minerals are distributed unevenly on earth and remain a precious form of natural resource to countries across the globe. Good quality and high-value minerals are relatively lesser existing than low-value minerals. Minerals are available in finite quantities are non-renewable and exhaustible. This calls for sensible and judicious use of minerals. 

Major mineral regions across India

India has huge reserves of metallic and non-metallic minerals. Mining is an essential economic activity in India, and it contributes to around 2.5% of the Indian GDP. In terms of the volume of mineral production, India ranks 4th in the world. India produces around 90 minerals, including 10 metallic and 47 non-metallic minerals. Eleven states, including Andhra Pradesh, Gujarat, Madhya Pradesh, Jharkhand, Rajasthan, Karnataka, Tamil Nadu, Orissa, Maharashtra, Chhattisgarh, and West Bengal, hold more than 90% of mines in India. A vast majority of the resources are found in the crystalline rocks of the peninsular plateau region. 

On the whole, the distribution in India can be brought under three different mineral belts – 

• North-Eastern plateau region 

This belt is rich in Kyanite, Iron Ore, Chromium, Mica, Coal and comprises the Chota Nagpur Plateau in Jharkhand, Odisha Plateau, and West Bengal. It also extends to include Assam which holds the reserves of petroleum and coal. 

• North-Western region

This belt comprises areas in Rajasthan and Gujarat covered by the Aravalli Range and is rich in salt, Copper, and Zinc. Rajasthan is known for building stones, and Gujarat is rich in petroleum deposits. Dolomite and limestone found in Rajasthan provide raw materials to the cement industry in India. 

• South-Western Plateau region

Known for holding iron ore, bauxite, manganese, limestone, and some ferrous metals, this region includes regions in Karnataka like Chikmagalur, Tumkur, Shimoga, and Goa. It also covers some parts of Tamil Nadu and Kerala.   

Distribution of Ferrous Minerals in India

Iron ore

India holds the largest share of iron ore in Asia. What is more important is that the Indian iron ores have a very high iron content (more than 60%). These iron ore mines are located very close to the coal mines in the north-eastern plateau region, which benefits the industries. 

There are three kinds of iron ore in India : 

95% of total iron ore reserves are found in Orissa, Chhattisgarh, Jharkhand, Goa, Karnataka, Telangana, and Andhra Pradesh. 

Manganese 

Orissa leads in the production of Manganese, followed by Karnataka, Maharashtra, and Madhya Pradesh. Other producers include Telangana, Jharkhand and Goa.