What is a mineral and how is it found
The toothpaste you used this morning, the steel bus you rode and the pin on your notice board all began as minerals dug out of the ground.
A mineral is a naturally occurring substance with a definable internal structure. Minerals are found mixed with other materials in ores; an ore is mined only when its mineral content is rich enough to make extraction pay.
Key idea 1: Mineral and ore — Rocks are combinations of minerals; limestone is a rock made of a single mineral, but most rocks hold several. Over 2000 minerals are known, yet only a few are abundant. Minerals differ in colour, hardness, crystal form, lustre and density because they form under different physical and chemical conditions, and geologists use these properties to classify them. A mineral deposit becomes a mine only when the concentration in the ore, the ease of extraction and the nearness to the market make it worth working.
- Easy: A rock made of a single mineral is limestone.
- Medium: An ore is a mineral mixed with other elements.
- Exam-type: A deposit is far from any market and very poor in mineral content, so it is not mined even though the mineral is present.
Key idea 2: Where minerals occur — In igneous and metamorphic rocks they fill cracks and joints: smaller occurrences are veins, larger ones are lodes (tin, copper, zinc, lead). In sedimentary rocks they lie in beds or layers: coal and some iron ore from long heat and pressure; gypsum, potash salt and sodium salt from evaporation in dry regions. Bauxite forms by decomposition of surface rocks, which leaves a residue of weathered material. Placer deposits are alluvial deposits in sands of valley floors and hill bases and hold minerals that water does not corrode: gold, silver, tin, platinum. Ocean water gives common salt, magnesium and bromine, and the ocean floor has manganese nodules.
- Easy: Gold and platinum are found in placer deposits.
- Medium: Gypsum and potash salt form when water evaporates in arid regions.
- Exam-type: A mineral formed by weathering of surface rocks that leaves a residue is bauxite.
Veins and lodes = igneous or metamorphic; beds and layers = sedimentary; placer = river sands; residue = bauxite.
Thinking all minerals of the sea are easy to extract. Most are too thinly spread; only salt, magnesium and bromine are mainly taken.
Match the rock to the way the mineral sits. Memory clue: "Vein-Fire, Bed-Water, Placer-River".
Spot the difference
| Mode | Where | Example |
|---|---|---|
| Veins and lodes | cracks in igneous and metamorphic rocks | copper, zinc, lead, tin |
| Beds and layers | sedimentary rocks | coal, gypsum, potash salt |
| Residual weathering | surface rocks decompose | bauxite |
| Placer deposits | valley-floor sands | gold, silver, platinum |
Practice questions
- 1What is an ore?
- 2Name one mineral found in placer deposits.
- 3What are the smaller and larger mineral occurrences in cracks called?
- 4How do gypsum and potash salt form?
- 5Why are most minerals of ocean water not mined?
- 6What makes a mineral deposit turn into a mine?
- 7Explain how minerals occur in igneous and metamorphic rocks.
- 8Why do minerals differ so widely in colour and hardness?
Show answers (try them yourself first)
- 1An accumulation of a mineral mixed with other elements.
- 2Gold, silver, tin or platinum.
- 3Veins (smaller) and lodes (larger).
- 4By evaporation, especially in arid regions.
- 5They are too widely diffused to be of economic use.
- 6A rich enough concentration, easy extraction and closeness to the market.
- 7Molten and gaseous minerals are forced up through cracks and joints, cool and solidify as veins and lodes, e.g. copper and zinc.
- 8They form under different physical and chemical conditions.
Ferrous, non-ferrous and non-metallic minerals
The iron in a railway track, the aluminium in a foil wrapper, the copper in a cable and the mica in an electric iron each come from a different place.
Ferrous minerals (iron ore, manganese) are the base of the steel industry. Non-ferrous minerals (copper, bauxite, lead, zinc, gold) serve metallurgical and electrical industries. Non-metallic and rock minerals include mica and limestone.
Key idea 1: Iron ore and manganese — Ferrous minerals give about three-fourths of the value of metallic mineral output. Magnetite is the finest iron ore (up to 70 per cent iron, magnetic, useful in the electrical industry); hematite is the most used in industry (50-60 per cent iron). In 2018-19, 97 per cent of iron ore came from Odisha, Chhattisgarh, Karnataka and Jharkhand. Belts: Odisha-Jharkhand (Badampahar; Gua and Noamundi), Durg-Bastar-Chandrapur (Bailadila hills, exported to Japan and South Korea via Visakhapatnam), Ballari-Chitradurga-Chikkamagaluru-Tumakuru (Kudremukh, a 100 per cent export unit, ore sent as slurry by pipeline to a port near Mangaluru) and Maharashtra-Goa (exported through Marmagao). Manganese goes into steel (about 10 kg per tonne), bleaching powder, insecticides and paints.
- Easy: Magnetite is the finest iron ore.
- Medium: Kudremukh ore travels as slurry through a pipeline to a port near Mangaluru.
- Exam-type: A steel plant wants the iron ore with the highest iron content and magnetic properties; it should choose magnetite.
Key idea 2: Non-ferrous and non-metallic — India is critically short of copper (malleable, ductile, a good conductor): leading mines are Balaghat (Madhya Pradesh), Khetri (Rajasthan) and Singhbhum (Jharkhand). Bauxite, a clay-like substance, gives alumina and then aluminium, which is strong, light and conducting; Odisha gave about 65 per cent in 2018-19 (Panchpatmali, Koraput), and deposits lie in Amarkantak, Maikal and Bilaspur-Katni. Mica splits into thin sheets and is vital for electrical and electronic industries (Koderma-Gaya-Hazaribagh in Jharkhand, Ajmer in Rajasthan, Nellore in Andhra Pradesh). Limestone is raw material for cement and is needed to smelt iron ore in a blast furnace.
- Easy: Bauxite is the ore of aluminium.
- Medium: Mica is used in electrical industries because it insulates well.
- Exam-type: A cement factory needs limestone as its basic raw material.
Ferrous = iron family and steel; non-ferrous = copper, bauxite, lead, zinc, gold; mica and limestone are non-metallic and rock minerals.
Calling manganese non-ferrous. It is a ferrous mineral used in steel.
Pair mineral with place. Memory clue: "Iron-Odisha, Copper-Balaghat, Bauxite-Odisha, Mica-Koderma".
Spot the difference
| Mineral | Group | Main use |
|---|---|---|
| Iron ore | ferrous | steel making |
| Manganese | ferrous | steel, bleaching powder |
| Copper | non-ferrous | electrical cables |
| Bauxite | non-ferrous | aluminium |
| Mica | non-metallic | electrical insulation |
Practice questions
- 1Name the finest iron ore.
- 2Which ore gives aluminium?
- 3Which state leads in bauxite output?
- 4Name two copper-mining areas.
- 5Why is mica important in industry?
- 6How is Kudremukh ore transported?
- 7Compare magnetite and hematite.
- 8Why does India depend on imports of copper?
Show answers (try them yourself first)
- 1Magnetite.
- 2Bauxite.
- 3Odisha.
- 4Balaghat, Khetri or Singhbhum.
- 5It insulates well and resists high voltage, so it suits electric and electronic industries.
- 6As slurry through a pipeline to a port near Mangaluru.
- 7Magnetite has up to 70 per cent iron and is magnetic; hematite has 50-60 per cent and is the most used in quantity.
- 8India is critically deficient in copper reserves and production.
Hazards of mining and conserving minerals
A miner breathes dust all day, and a stream near a mine runs muddy. Cheap minerals often have a hidden cost.
Mineral conservation means using non-renewable mineral resources in a planned way so they last longer, and keeping mining safe for miners and the environment.
Key idea 1: Hazards of mining — Dust and noxious fumes cause lung diseases in miners. Collapsing roofs, flooding and fires in coal mines are a constant danger. Mining contaminates water, and dumped waste and slurry degrade land and soil and pollute streams and rivers. Stricter safety rules and environmental laws are needed so mining does not become a "killer industry". In Meghalaya, family-run "rat-hole" coal mining in narrow tunnels has been declared illegal by the National Green Tribunal.
- Easy: Dust inhaled in mines causes lung disease.
- Medium: Dumped mine slurry pollutes rivers.
- Exam-type: A mine pumps its waste into a stream, so villagers downstream face polluted water and degraded land.
Key idea 2: Why conserve — Workable minerals are only about one per cent of the earth's crust. They took millions of years to form, but we are using them far faster than they form, so they are finite and non-renewable. Continued mining means rising costs and falling quality as extraction goes deeper. Conservation means planned use, better technology to use low-grade ores cheaply, recycling of metals, using scrap and finding substitutes.
- Easy: Minerals are non-renewable.
- Medium: Recycling metals saves mineral resources.
- Exam-type: Using scrap metal instead of fresh ore is a conservation step because it reduces mining.
Minerals form over millions of years but are used in a short time; hence plan, recycle and substitute.
Thinking minerals will renew like forests. Replenishment is infinitely small compared with consumption.
Conserve with 3 steps. Memory clue: "Plan, Recycle, Replace".
Spot the difference
| Problem | Cause | Remedy |
|---|---|---|
| Miner's lung disease | dust and fumes | safety rules |
| Water pollution | waste and slurry | environmental laws |
| Running out | fast use of finite stock | recycling, substitutes |
Practice questions
- 1Are minerals renewable or non-renewable?
- 2What disease risk does mining dust cause?
- 3What is rat-hole mining?
- 4How does mining spoil water?
- 5Give one way to conserve minerals.
- 6Why does mining cost rise over time?
- 7Explain why mining can be called a "killer industry".
- 8Why are minerals called short-lived possessions?
Show answers (try them yourself first)
- 1Non-renewable.
- 2Lung (pulmonary) diseases.
- 3Family mining of coal through long narrow tunnels in Meghalaya, declared illegal by the NGT.
- 4Waste and slurry are dumped and pollute streams and rivers.
- 5Recycling, using scrap, or substitutes.
- 6Ore comes from greater depths and its quality falls.
- 7It causes lung disease, roof collapses, flooding and fires, and harms water and land.
- 8They took millions of years to form but are being used up far faster than they renew.
Conventional energy: coal, petroleum, gas and electricity
The gas in your kitchen, the petrol in a scooter and the light in your room all trace back to fuels from the ground or to flowing water.
Conventional energy comes from firewood, dung cakes, coal, petroleum, natural gas and electricity (hydel and thermal).
Key idea 1: Coal — Coal is India's most abundant fossil fuel, used for power, industry and homes. It forms from compressed plant material, so its type depends on compression and depth: peat (low carbon, high moisture), lignite (soft brown coal; Neyveli in Tamil Nadu, used for electricity), bituminous (most popular in commerce; the high-grade metallurgical kind smelts iron) and anthracite (best hard coal). Gondwana coal (a little over 200 million years old) is in the Damodar valley (Jharia, Raniganj, Bokaro) and the Godavari, Mahanadi, Son and Wardha valleys; tertiary coal (about 55 million years) is in the north-east. Coal loses weight as ash, so heavy industries and thermal stations stand near coalfields.
- Easy: Neyveli is known for lignite.
- Medium: Jharia and Raniganj are Gondwana coalfields in the Damodar valley.
- Exam-type: A thermal power station is built near a coalfield because coal is bulky and loses weight on burning.
Key idea 2: Petroleum, natural gas and electricity — Petroleum is next after coal and feeds a "nodal industry" for synthetic textiles, fertilisers and chemicals. It is trapped in anticlines and fault traps in tertiary rocks; Mumbai High, Gujarat (Ankleshwar) and Assam (Digboi, Naharkatiya, Moran-Hugrijan; the oldest oil state) are the main areas. Natural gas comes with petroleum and is used in power, industry, as CNG and PNG; major reserves are Mumbai High and the Krishna-Godavari basin, linked by pipelines such as the 1,700 km HVJ line. Electricity comes from hydel (flowing water, renewable) or thermal (coal, petroleum, gas; non-renewable) stations, and per capita use shows development.
- Easy: Assam is the oldest oil-producing state.
- Medium: Hydro-electricity uses flowing water, a renewable resource.
- Exam-type: A refinery supports fertiliser and synthetic textile industries, so it is called a nodal industry.
Coal ranks: peat, lignite, bituminous, anthracite. Oil traps: anticlines and faults.
Calling thermal electricity renewable. It burns fossil fuels.
Link fuel to place: coal-Damodar, lignite-Neyveli, oil-Mumbai High and Assam. Memory clue: "Pet-Lig-Bit-Anth, quality goes up".
Spot the difference
| Fuel | Key fact | Place |
|---|---|---|
| Lignite | soft brown coal | Neyveli |
| Gondwana coal | about 200 million years | Damodar valley |
| Petroleum | in anticline and fault traps | Mumbai High, Assam |
| Natural gas | with oil, CNG and PNG | Krishna-Godavari |
Practice questions
- 1Name India's most abundant fossil fuel.
- 2Which state is the oldest oil producer?
- 3What is the best quality hard coal?
- 4Why are thermal stations near coalfields?
- 5What is a nodal industry in petroleum?
- 6Name one gas reserve region.
- 7Describe the distribution of Gondwana coal.
- 8Distinguish hydel and thermal electricity.
Show answers (try them yourself first)
- 1Coal.
- 2Assam.
- 3Anthracite.
- 4Coal is bulky and loses weight on burning, so moving it is costly.
- 5The refinery, because synthetic textile, fertiliser and chemical industries depend on it.
- 6Mumbai High or the Krishna-Godavari basin.
- 7Damodar valley (Jharia, Raniganj, Bokaro) and Godavari, Mahanadi, Son and Wardha valleys.
- 8Hydel uses flowing water (renewable); thermal burns coal, oil or gas (non-renewable).
Conventional energy: coal, petroleum, gas and electricity
In the app you can move this figure with your finger.
Open in the appNon-conventional energy and saving energy
A rooftop solar heater, a village biogas stove and a spinning wind turbine all give power without burning coal or oil.
Non-conventional energy comes from renewable sources: solar, wind, tide, biogas, geothermal and nuclear (atomic) power, which reduce dependence on fossil fuels.
Key idea 1: Solar, wind, nuclear and biogas — Solar energy uses photovoltaic cells to turn sunlight into electricity and suits rural and remote areas. Wind power: the largest wind-farm cluster is in Tamil Nadu from Nagercoil to Madurai; Nagercoil and Jaisalmer are well known. Nuclear power uses uranium and thorium found in Jharkhand and the Aravalli ranges; monazite sands of Kerala are rich in thorium. Biogas is made from farm waste, animal and human waste, with more heat efficiency than kerosene or dung cakes; gobar gas plants give energy and better manure.
- Easy: Photovoltaic cells convert sunlight into electricity.
- Medium: Nagercoil has India's largest wind-farm cluster, from Nagercoil to Madurai.
- Exam-type: A farmer using gobar gas gets both cooking fuel and better manure.
Key idea 2: Tidal, geothermal and saving energy — Tidal energy traps high-tide water behind floodgates and releases it through a turbine; good sites are the Gulf of Khambhat, the Gulf of Kuchchh and the Sunderban delta. Geothermal energy uses earth's inner heat: groundwater heated by hot rocks rises as steam to drive turbines; experimental plants are at Manikaran (Parvati valley) and Puga valley (Ladakh). India is among the least energy-efficient countries, so we must save energy: use public transport, switch off unused power, use power-saving devices and renewable sources. "Energy saved is energy produced."
- Easy: Puga valley in Ladakh has a geothermal project.
- Medium: Tidal plants need floodgates across inlets.
- Exam-type: Taking a bus instead of a private car saves fuel, so it is an energy-conservation step.
Solar, wind, tide, biogas and geothermal renew themselves; sustainable energy means saving plus renewables.
Thinking firewood is a non-conventional source. Firewood and dung cake are conventional.
Pair source with place: wind-Nagercoil, tide-Khambhat, geothermal-Puga, thorium-Kerala. Memory clue: "Wind Nagercoil, Tide Khambhat, Heat Puga".
Spot the difference
| Source | Place | Key fact |
|---|---|---|
| Wind | Tamil Nadu | largest wind-farm cluster |
| Tidal | Khambhat, Kuchchh, Sunderban | floodgate dams |
| Geothermal | Manikaran, Puga | hot groundwater to steam |
| Nuclear | Jharkhand, Rajasthan, Kerala | uranium, thorium |
Practice questions
- 1What does photovoltaic technology do?
- 2Name one geothermal project site.
- 3What is a gobar gas plant?
- 4Where is India's largest wind-farm cluster?
- 5Name two tidal energy sites.
- 6Which minerals fuel nuclear power?
- 7Why does solar energy have a bright future in India?
- 8Give three ways citizens can save energy.
Show answers (try them yourself first)
- 1It converts sunlight directly into electricity.
- 2Manikaran in Himachal Pradesh or Puga valley in Ladakh.
- 3A biogas plant using cattle dung that gives energy and better manure.
- 4Tamil Nadu, from Nagercoil to Madurai.
- 5Gulf of Khambhat, Gulf of Kuchchh or Sunderban delta.
- 6Uranium and thorium.
- 7India is tropical with abundant sunlight, and solar plants reduce use of firewood and dung cakes.
- 8Use public transport, switch off unused power and use power-saving devices.