Consider the following minerals: 1. Bentonite 2. Chromite 3. Kyanite 4. Sillimanite In India, which of the above is/are officially designated as major minerals?
Contents10
- A1 and 2 only
- B4 only
- C1 and 3 only
- D2, 3 and 4 only
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Answer: (D) 2, 3 and 4 only
Chromite, Kyanite, and Sillimanite are major minerals.
Bentonite is a highly plastic clay and is declared as a 'Minor Mineral' by the Government of India.
India classifies minerals into major and minor categories, which determines whether the central or state government has jurisdiction over mining leases and royalties.
In 2015, the government specifically reclassified bentonite from major to minor mineral status, making it a key exam trap since students often assume all industrial minerals are major.
The question tests whether students know the specific 2015 notification change for bentonite versus the established major mineral status of chromite, kyanite, and sillimanite.
Major vs Minor Minerals Classification
Geography major minerals minor minerals
Major vs Minor Minerals: Classification System in India
Major minerals are strategically important, centrally regulated under MMDR Act 1957
Minor minerals are locally important, regulated by state governments
Bentonite was reclassified as minor mineral in 2015
Classification determines licensing authority and regulatory framework
India classifies minerals into Major and Minor categories based on strategic importance and economic value. This classification determines which government level controls mining licenses and regulation.
Key Differences
Aspect | Major Minerals | Minor Minerals |
|---|---|---|
Regulatory Authority | Central Government | State Governments |
Legal Framework | MMDR Act 1957 | State Minor Mineral Rules |
Strategic Importance | High economic/industrial value | Local construction/building materials |
Examples | Coal, Iron ore, Chromite, Kyanite | Sand, Stone, Clay, Bentonite |
License Type | Mining lease from Centre | Quarry lease from State |
The 2015 government notification reclassified Bentonite from major to minor mineral status. This shift reflects its primary use in construction and ceramics rather than strategic industries.
Bentonite trap: Sounds industrial/important but was reclassified as minor in 2015
Don't assume all metallic minerals are major - classification depends on strategic value
Chromite is always major - India is a major global producer
Kyanite & Sillimanite are both aluminosilicate refractories - both major minerals
Bentonite: Properties & Applications
Geography Bentonite
Bentonite: The Versatile Clay Mineral
Bentonite is a clay mineral formed from volcanic ash weathering
Classified as minor mineral in India since 2015
Major uses: drilling mud, construction, foundry sand
Bentonite is a clay mineral formed by weathering of volcanic ash. Its unique swelling properties when mixed with water make it valuable for industrial applications, though not strategically critical enough to remain a major mineral.
Key Properties & Uses
High swelling capacity - absorbs water and expands significantly
Drilling mud - used in oil/gas drilling for borehole stability
Foundry applications - binding agent in metal casting
Construction industry - waterproofing and sealing applications
Cat litter and cosmetics - absorbent properties
India produces bentonite mainly in Gujarat, Rajasthan, and Himachal Pradesh. The 2015 reclassification as minor mineral transferred regulatory control to state governments, reflecting its local construction-focused applications.
Chromite: Strategic Metal Ore
Geography Chromite
Chromite: India's Strategic Chromium Resource
Chromite is the only commercial ore of chromium
Essential for stainless steel and aerospace industries
India holds world's largest chromite reserves in Odisha
Chromite (FeCr₂O₄) is the sole commercially viable source of chromium metal. Its strategic importance in steel production and defense applications makes it a permanently classified major mineral.
Strategic Applications
Stainless steel production - chromium provides corrosion resistance
Aerospace industry - high-temperature alloys for jet engines
Refractory materials - furnace linings in steel plants
Chemical industry - chromium compounds and pigments
Defense applications - armor plating and military equipment
India possesses the world's largest chromite reserves, concentrated in the Sukinda Valley, Odisha. The Boula-Nuasahi mines are among the largest chromite deposits globally, making India a major exporter despite domestic steel industry demand.
Chromite Distribution
Map of India showing major chromite mining areas, particularly highlighting Sukinda Valley in Odisha and other deposits in Karnataka and Manipur
Sukinda Valley, Odisha contains India's largest chromite reserves - over 95% of national production
Aluminosilicate Minerals: Kyanite & Sillimanite
Geography Kyanite Sillimanite
Kyanite & Sillimanite: High-Grade Refractory Minerals
Kyanite & Sillimanite are aluminum silicate minerals (Al₂SiO₅)
Both classified as major minerals due to refractory applications
Essential for high-temperature ceramics and steel industry
Kyanite and Sillimanite share the same chemical formula (Al₂SiO₅) but differ in crystal structure. Both are refractory minerals - materials that withstand extremely high temperatures without losing strength.
Kyanite vs Sillimanite
Property | Kyanite | Sillimanite |
|---|---|---|
Crystal System | Triclinic | Orthorhombic |
Color | Blue to white | Brown to pale green |
Hardness | 4-7 (variable) | 6-7 (uniform) |
Main Use | Refractory bricks | High-grade ceramics |
Indian Deposits | Jharkhand, Karnataka | Odisha, Assam |
Industrial Applications
Steel industry - refractory linings for blast furnaces and ladles
Ceramic industry - high-temperature porcelain and technical ceramics
Glass industry - furnace construction and repair
Aerospace - heat-resistant components and thermal barriers
Automotive - spark plug insulators and engine components
India is among the top global producers of both minerals. Jharkhand leads in kyanite production, while Odisha and Assam are major sillimanite producers. Their strategic importance in high-temperature industrial applications ensures major mineral status.