UPSC CSE Prelims
Rocks and Minerals Previous Year Questions (PYQs)

Detailed Explanation:

Explanation:

• Statement 1 is Correct: Rare Earth Elements (REEs) are essential for modern technologies such as Artificial Intelligence, robotics, electric vehicles, renewable energy systems, space exploration, and defense equipment.

• Statement 2 is Incorrect: China is the largest producer of REEs, but the United States is the second-largest producer. India is not the second-largest producer globally.

• Statement 3 is Correct: The Government of India launched the National Critical Mineral Mission (NCMM) in January 2025 to strengthen domestic production, secure supply chains, and reduce import dependence.

• Statement 4 is Incorrect: Rare Earth Elements consist of 17 elements—15 lanthanides along with scandium and yttrium—not 13 elements.

• Therefore, statements 1 and 3 are correct, making Option A the correct answer.

Rare Earth Elements (REEs) and Critical Minerals

• REEs are a group of 17 metallic elements used in high-tech industries, clean energy technologies, electronics, and defense systems.

• Critical minerals are minerals essential for economic security and strategic industries, with limited supply sources and high import dependence.

Detailed Explanation:

Correct Answer: ✅ Option 3

Chalk and clay differ mainly in permeability, not simply in porosity. Chalk contains many interconnected pores, allowing water to pass through easily. Clay also has pores, but they are extremely small and poorly connected, so water movement is very slow. Therefore, Statement II is correct and explains Statement I, while Statement III is incorrect.

✅ Statement I is Correct: Chalk is highly permeable, whereas clay is one of the least permeable rocks/soils.

✅ Statement II is Correct: Chalk is porous and can absorb and transmit water through its interconnected pore spaces.

❌ Statement III is Incorrect: Clay is not non-porous; it is porous but has very tiny pores that restrict water movement.

Short Notes: Porosity and Permeability

• Porosity is the percentage of pore spaces in a rock or soil.

• Permeability is the ability of water to move through those pore spaces.

• A rock can be porous but impermeable if pores are not well connected.

• Chalk is both porous and permeable.

• Clay is porous but largely impermeable due to tiny pore size.

• Groundwater is commonly stored in porous and permeable rocks called aquifers.

• Sandstone and chalk are common aquifer rocks.

Detailed Explanation:

Answer: Option 4 — 2, 3 and 4 only

In India, major minerals are those specified in the First Schedule of the Mines and Minerals (Development and Regulation) Act, 1957. Bentonite is classified as a minor mineral, while Chromite, Kyanite, and Sillimanite are all major minerals.

1. Bentonite – Minor Mineral: Bentonite is a clay mineral used in drilling mud, foundry sand, and civil engineering applications. It is listed under minor minerals.

2. Chromite – Major Mineral ✅: Chromite is the only ore of chromium and is essential for manufacturing stainless steel and various alloys. It is a major mineral.

3. Kyanite – Major Mineral ✅: Kyanite is a refractory mineral used in ceramics and high-temperature industrial applications. It is classified as a major mineral.

4. Sillimanite – Major Mineral ✅: Sillimanite is another refractory mineral with applications in metallurgy and industrial furnaces. It is a major mineral.

📝 Short Notes: Major vs Minor Minerals in India

• Refractory Minerals: Kyanite and Sillimanite are aluminum silicate minerals with high heat resistance, crucial for refractory (heat-resistant) materials.
• Chromite in India: India has significant chromite reserves, mainly in Odisha (about 98% of national reserves).
• MMDR Amendment 2015: Provided greater transparency in mineral allocation through auction mechanism for major minerals.