Rocks & Minerals – NDA Geography PYQs

NDA 2025-II

Q. 1. Consider the following statements with reference to Feldspar mineral:

1. Half of the Earth’s crust is composed of feldspar.

2. It has light cream to salmon pink colour.

3. Magnesium is a common element in all types of feldspar.

Which of the statements given above is/are correct?

(a) 1 only

(b) 1 and 2 only

(c) 2 and 3 only

(d) 1, 2 and 3

Answer: (b) 1 and 2 only

Explanation: Statement 1 (About half the crust is feldspar): Correct. Feldspars are the most abundant mineral group in Earth’s crust, comprising approximately 41–60% of crustal rock minerals. Statement 2 (Light cream to salmon pink colour): Correct. Feldspars commonly have light cream, white, grey, or salmon pink colours. Potassium feldspar (orthoclase) is often distinctively pink. Statement 3 (Magnesium in all types of feldspar): Incorrect. Feldspars contain Potassium (K), Sodium (Na), and Calcium (Ca): not Magnesium (Mg). Magnesium is found in minerals like olivine, pyroxene, and amphibole: not in feldspars. Concept Tested: Feldspar: most abundant crustal mineral (~41%+); cream to pink colour; contains K/Na/Ca but NOT magnesium

Q. 2. Consider the following pairs with reference to sedimentary rocks and the process of their formation:

Sedimentary Rock	Process of Formation
1. Chert	Chemically formed
2. Geyserite	Organically formed
3. Shale	Mechanically formed

Which of the pairs given above is/are correctly matched?

(a) 1 only

(b) 1 and 2 only

(c) 2 and 3 only

(d) 1, 2 and 3

Answer: (a) 1 only

Explanation: Pair 1 (Chert: Chemically formed): Correct. Chert is a chemical/biochemical sedimentary rock formed from silica precipitation. ✓ Pair 2 (Geyserite: Organically formed): Incorrect. Geyserite (siliceous sinter) is a chemical deposit formed by silica-rich hot spring water precipitating silica around geysers and hot springs. It is NOT organically formed. Pair 3 (Shale: Mechanically formed): Shale is a clastic (mechanical) sedimentary rock formed from the compaction of clay and silt particles: this is correct. However, the source records only Pair 1 as the answer. Students should verify Pair 3 against the official NDA 2025-II answer key. Concept Tested: Sedimentary rock processes: Chert (chemical) correct; Geyserite is chemical (not organic); Shale is mechanical

NDA 2025-I

Q. 3. Which of the following is the correct ascending order of the given minerals in terms of their presence in the Earth’s crust?

1. Amphibolite

2. Mica

3. Pyroxene

Select the answer using the code given below:

(a) 2, 3, 1

(b) 1, 2, 3

(c) 2, 1, 3

(d) 1, 3, 2

Answer: (a) 2, 3, 1

Explanation: In ascending order (least to most abundant in Earth’s crust): Mica (2): least abundant among the three, contributing ~4–5% of crustal minerals. Pyroxene (3): moderately abundant, ~11% of crustal composition. Amphibolite/Amphibole group (1): among the more abundant silicate groups, ~5–17% of the crust depending on classification. The source records the ascending order as Mica → Pyroxene → Amphibolite = 2, 3, 1. Students should verify the exact percentages against standard mineralogy references before publication. Concept Tested: Crustal mineral abundance (ascending): Mica < Pyroxene < Amphibolite; source records 2, 3, 1

Q. 4. Which one of the following is formed when volcanic ash is carried by running water and is deposited as a sedimentary layer?

(a) Basalt

(b) Lapilli

(c) Slate

(d) Tuff

Answer: (d) Tuff

Explanation: Tuff (also called volcanic tuff or ash-fall tuff) is a sedimentary rock formed when volcanic ash is carried by wind or running water and deposited in layers. When this ash settles and compacts, it forms tuff. Lapilli are small rock fragments (2–64 mm) ejected during volcanic eruptions: not a sedimentary deposit. Slate is a metamorphic rock. Basalt is an extrusive igneous rock. Concept Tested: Tuff: formed from volcanic ash deposited by water/wind; a pyroclastic sedimentary rock

NDA 2024-II

Q. 5. Which one of the following is an example of both an igneous as well as a metamorphic rock?

(a) Gabbro

(b) Geyserite

(c) Gneissoid

(d) Granite

Answer: (d) Granite

Explanation: The source records Granite as the answer. Granite is primarily an igneous rock. However, the term “Gneissoid Granite” or granitic gneiss refers to granite that has been partially or fully metamorphosed: exhibiting both igneous composition and metamorphic texture. Some granites formed during regional metamorphism are considered “metamorphic granites” or migmatites. Gneissoid (c) is a textural term for rocks with gneiss-like banding: it is metamorphic. The source answer is (d) Granite. Students should verify this against the official NDA 2024-II answer key. Concept Tested: Granite: primarily igneous, but also classified as metamorphic in certain geological contexts; verify against official key

Q. 6. Which one of the following is correct?

(a) Pyroxene is commonly found in meteorites

(b) Amphiboles form about 20% of the Earth’s crust

(c) Quartz is soluble in water

(d) The word ‘sedimentary’ is derived from the Latin word ‘kelimentum’

Answer: (a) Pyroxene is commonly found in meteorites

Explanation: (a) Pyroxene is commonly found in meteorites: Correct. Pyroxenes are silicate minerals that occur in many rock types including meteorites (particularly chondrites and achondrites). (b) Amphiboles form about 20% of the Earth’s crust: Incorrect. Feldspars make up about 41% of the crust; amphiboles are far less abundant. (c) Quartz is soluble in water: Incorrect. Quartz (SiO₂) is one of the most resistant and insoluble minerals under normal surface conditions. (d) ‘Sedimentary’ from Latin ‘kelimentum’: Incorrect. ‘Sedimentary’ derives from the Latin ‘sedimentum’ meaning ‘settling’ or ‘that which settles’. Concept Tested: Pyroxene is found in meteorites; amphiboles are not 20% of crust; quartz is insoluble; ‘sedimentum’ (not kelimentum)

NDA 2023-I

Q. 7. Which one of the following is not an igneous rock?

(a) Granite

(b) Slate

(c) Basalt

(d) Gabbro

Answer: (b) Slate

Explanation: Slate is a metamorphic rock: formed from the metamorphism of shale under low-grade heat and pressure. Granite (a): intrusive igneous rock ✓. Basalt (c): extrusive igneous rock ✓. Gabbro (d): intrusive igneous rock (dark coloured, coarse-grained) ✓. Concept Tested: Slate is metamorphic (from shale): not igneous; Granite, Basalt, Gabbro are all igneous

NDA 2020-I

Q. 8. Chalk and marble are different forms of:

(a) Calcium hydrogen carbonate

(b) Calcium carbonate

(c) Calcium acetate

(d) Sodium carbonate

Answer: (b) Calcium carbonate

Explanation: Both Chalk and Marble are composed primarily of calcium carbonate (CaCO₃): but in different forms: Chalk: a soft, fine-grained, organically formed sedimentary rock (calcium carbonate from marine organism shells). Marble: a metamorphic rock formed from the recrystallisation of limestone or chalk under heat and pressure. Both are thus different forms of calcium carbonate. Concept Tested: Chalk (sedimentary) and Marble (metamorphic) are both forms of calcium carbonate (CaCO₃)

NDA 2019-II

Q. 9. Which one of the following sedimentary rocks is organically formed?

(a) Shale

(b) Chert

(c) Halite

(d) Chalk

Answer: (d) Chalk

Explanation: Chalk is an organically formed sedimentary rock: it is composed of the microscopic calcium carbonate shells of marine organisms (coccolithophores: tiny planktonic algae). These shells accumulate on the sea floor and eventually form chalk. Shale is a mechanically formed (clastic) sedimentary rock: deposited clay and silt particles. Chert is chemically or biologically formed (siliceous: from silica precipitating from water or from radiolarian/diatom remains). Halite is chemically formed (evaporite: formed when saltwater evaporates). Concept Tested: Chalk: organically formed sedimentary rock from marine organism shells (calcium carbonate)

NDA 2018-II

Q. 10. Which one of the following is not an agent of metamorphism?

(a) Heat

(b) Compression

(c) Decomposition

(d) Solution

Answer: (c) Decomposition

Explanation: Metamorphism is the process by which existing rocks are transformed by heat, pressure, and chemically active fluids: without melting. The principal agents of metamorphism are: Heat: from magma intrusion or deep burial. Pressure/Compression: from tectonic forces or burial. Chemically active solutions: hot fluids carrying ions that alter rock chemistry. Decomposition is a chemical weathering process (breaking down of minerals at the surface): it is the OPPOSITE of metamorphism and is not an agent of it. Concept Tested: Agents of metamorphism: Heat, Pressure, Chemically active solutions; Decomposition is NOT one

NDA 2017-II

Q. 11. Which one of the following is not an igneous rock?

(a) Gabbro

(b) Granite

(c) Dolomite

(d) Basalt

Answer: (c) Dolomite

Explanation: Dolomite is a carbonate sedimentary rock (or mineral) composed of calcium magnesium carbonate: CaMg(CO₃)₂. It is NOT an igneous rock. Gabbro (a), Granite (b), and Basalt (d) are all igneous rocks: Gabbro is a coarse-grained intrusive rock (dark coloured); Granite is coarse-grained intrusive (light coloured); Basalt is fine-grained extrusive. Concept Tested: Dolomite is a carbonate sedimentary rock: not igneous; Gabbro, Granite, Basalt are igneous

NDA 2014-II

Q. 12. Quartzite is metamorphosed from:

(a) limestone

(b) plutonic rock

(c) sandstone

(d) shale

Answer: (c) Sandstone

Explanation: Quartzite is a metamorphic rock formed from the metamorphism of sandstone under heat and pressure. The quartz grains in sandstone are recrystallised, forming a hard, compact quartzite. The key metamorphic pairs are: Limestone → Marble. Sandstone → Quartzite. Shale → Slate (low grade) → Phyllite → Schist → Gneiss (higher grades). Concept Tested: Quartzite is metamorphosed sandstone; Marble is metamorphosed limestone

NDA 2014-I

Q. 13. Statement I: Minerals are formed by slow cooling of the magma.

Statement II: Very small crystals are formed when lava cools quickly on the surface.

(a) Both the Statements are individually true and Statement II is the correct explanation of Statement I

(b) Both the Statements are individually true but Statement II is not the correct explanation of Statement I

(c) Statement I is true but Statement II is false

(d) Statement I is false but Statement II is true

Answer: (a) Both the Statements are individually true and Statement II is the correct explanation of Statement I

Explanation: Statement I: Correct. Minerals with large, well-formed crystals are formed when magma cools slowly underground, giving atoms time to arrange into crystal structures. Statement II: Correct. When lava cools rapidly on the surface, there is not enough time for large crystals to form, resulting in very small or microscopic crystals (or even glassy texture as in obsidian). Statement II explains why different cooling rates produce different crystal sizes: and thereby explains Statement I (slow cooling = larger minerals/crystals). Concept Tested: Crystal size and cooling rate: slow cooling = large crystals (intrusive); fast cooling = small crystals (extrusive)

Q. 14. What is the correct sequence from the smallest to the largest grain of the following types of clastic rocks?

(a) Shale, sandstone, conglomerate, siltstone

(b) Shale, siltstone, sandstone, conglomerate

(c) Conglomerate, sandstone, shale, siltstone

(d) Sandstone, siltstone, conglomerate, shale

Answer: (b) Shale, siltstone, sandstone, conglomerate

Explanation: Clastic sedimentary rocks are classified by grain size (smallest to largest): Shale: smallest grains (clay and silt particles <0.0625 mm). Siltstone: fine grains (0.0625–0.125 mm). Sandstone: medium grains (0.125–2 mm sand). Conglomerate: largest, rounded pebbles/gravel (>2 mm). Correct ascending order: Shale → Siltstone → Sandstone → Conglomerate. Concept Tested: Clastic rock grain size: Shale (finest) < Siltstone < Sandstone < Conglomerate (coarsest)

★ JOVIK Exam Insight Clastic sedimentary rock grain size ranking for NDA: Smallest → Largest: Shale → Siltstone → Sandstone → Conglomerate. Simple memory: S-S-S-C: Shale, Siltstone, Sandstone, Conglomerate.

NDA 2013-I

Q. 15. Radioactive decay provides an internal source of heat for the Earth. This helps in the formation of which type of rocks?

(a) Igneous

(b) Sedimentary

(c) Metamorphic

(d) All of the above

Answer: (a) Igneous

Explanation: Radioactive decay in the Earth’s interior generates heat. This internal heat melts rock to form magma. When magma cools and solidifies, it forms igneous rocks. Igneous rocks are therefore directly linked to internal heat: both intrusive (solidifying underground) and extrusive (erupting as lava). Sedimentary rocks form at or near the surface from deposited materials. Metamorphic rocks form from heat AND pressure applied to pre-existing rocks: both heat and pressure are needed, not just heat alone. Concept Tested: Radioactive decay generates internal heat → melts rock → forms magma → igneous rocks

NDA 2012-II

Q. 16. Which one among the following rocks does not belong to the same group?

(a) Shale

(b) Limestone

(c) Slate

(d) Sandstone

Answer: (c) Slate

Explanation: Shale, Limestone, and Sandstone are all sedimentary rocks. Slate is a metamorphic rock: it is formed from shale under pressure and temperature. Slate does not belong to the sedimentary group. Concept Tested: Slate is the odd one out: it is metamorphic; Shale, Limestone, Sandstone are all sedimentary

NDA 2011-II

Q. 17. Which of the following statements is/are correct?

1. The major constituent mineral of granite rock is quartz.

2. The major constituent mineral of sandstone rock is feldspar.

3. The major constituent mineral of limestone rock is dolomite.

Select the correct answer using the code given below:

(a) 1, 2 and 3

(b) 3 only

(c) 1 and 2 only

(d) 2 and 3 only

Answer: (c) 1 and 2 only

Explanation: Statement 1 (Granite’s major mineral = quartz): Correct in broad terms. Granite is a felsic rock containing quartz, feldspar, and mica. Quartz and feldspar are both major constituents; feldspar is actually more abundant by volume, but quartz is a definitive component. Accepted as correct in this NDA context. Statement 2 (Sandstone’s major mineral = feldspar): Note: Sandstone is actually composed mainly of quartz grains, not feldspar. However, the source records (c) 1 and 2 only as the answer: implying Statement 2 is treated as correct. Students should verify this against the official NDA 2011-II answer key. Statement 3 (Limestone’s major mineral = dolomite): Incorrect. Limestone is composed mainly of calcite (CaCO₃). Dolomite is a separate mineral (CaMg(CO₃)₂) and gives its name to a separate rock type (dolostone). Limestone is NOT primarily dolomite. Concept Tested: Limestone = calcite (NOT dolomite); granite and sandstone mineral compositions; verify Statement 2 against official key

Q. 18. Which one among the following is a primary rock?

(a) Sedimentary

(b) Igneous

(c) Metamorphic

(d) None of the above

Answer: (b) Igneous

Explanation: Igneous rocks are called “primary rocks” because they are the first rocks to form: directly from the solidification of molten magma or lava. All other rock types (sedimentary and metamorphic) are ultimately derived from igneous rocks or from each other through various geological processes. Sedimentary rocks form from the weathering and deposition of other rocks. Metamorphic rocks form from the alteration of pre-existing rocks by heat and pressure. Concept Tested: Igneous rocks are primary rocks: formed directly from magma; all other rock types are derived rocks

NDA 2010-II

Q. 19. Consider the following statements about rocks:

I. Shale becomes slate through metamorphosis.

II. Shale is converted to slate when it is subjected to tremendous pressure and high temperature.

Which of the statements given above is/are correct?

(a) I only

(b) II only

(c) Both I and II

(d) Neither I nor II

Answer: (c) Both I and II

Explanation: Statement I: Correct. Slate is the metamorphic rock formed from shale. Shale → Slate is a classic parent-metamorphic rock pair. Statement II: Correct. The metamorphism process requires both high pressure and elevated temperature. Shale, when buried deeply and subjected to these conditions, recrystallises into slate. Concept Tested: Shale → Slate: metamorphic transformation under high pressure and temperature

NDA 2010-I

Q. 20. Which one of the following is generally found in sedimentary rocks?

(a) Basalt

(b) Silica

(c) Shale

(d) Magnesium

Answer: (c) Shale

Explanation: Shale is a fine-grained clastic sedimentary rock composed mainly of clay minerals and silt. It is one of the most common sedimentary rocks. Basalt is an igneous rock. Silica is a mineral component found in many rock types (not specifically sedimentary). Magnesium is an element, not a rock. Concept Tested: Shale: a clastic sedimentary rock found commonly in geological sequences

NDA 2008-II

Q. 21. Match List I with List II and select the correct answer:

List I	List II
A. Slate	1. Igneous Rock
B. Lignite	2. Metamorphic Rock
C. Bauxite	3. Non-Ferrous Mineral
D. Granite	4. Sedimentary Rock

Codes:

(a) A-1, B-3, C-3, D-2

(b) A-2, B-4, C-3, D-1

(c) A-2, B-3, C-4, D-1

(d) A-1, B-4, C-3, D-2

Answer: (b) A-2, B-4, C-3, D-1

Explanation: Slate (A) → Metamorphic Rock (2). Slate is formed by the metamorphism of shale under pressure and moderate temperature. Lignite (B) → Sedimentary Rock (4). Lignite (brown coal) is an organic sedimentary rock: a low-rank coal. Bauxite (C) → Non-Ferrous Mineral (3). Bauxite is the ore of aluminium: a non-ferrous (non-iron) mineral. Granite (D) → Igneous Rock (1). Granite is a coarse-grained intrusive igneous rock. Concept Tested: Rock and mineral classification: Slate (metamorphic), Lignite (sedimentary), Bauxite (non-ferrous mineral), Granite (igneous)

NDA 2008-I

Q. 22. Consider the following statements:

1. Coal is a sedimentary rock.

2. Basalt is an igneous rock.

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer: (c) Both 1 and 2

Explanation: Statement 1: Correct. Coal is an organically formed sedimentary rock. It is formed from the accumulated organic matter (ancient plant material) that has been buried and compressed over millions of years. Statement 2: Correct. Basalt is an extrusive igneous rock formed when lava cools quickly on the Earth’s surface. Concept Tested: Coal (sedimentary, organic) and Basalt (extrusive igneous): both correctly classified

NDA 2007-I

Q. 23. Granite and Basalt are the examples of which of the following?

(a) Sedimentary rocks

(b) Metamorphic rocks

(c) Igneous rocks

(d) Calcareous rocks

Answer: (c) Igneous rocks

Explanation: Granite is an intrusive (plutonic) igneous rock: formed from slowly cooling magma deep within the Earth’s crust. Its slow cooling produces large, visible crystals (coarse-grained). Basalt is an extrusive (volcanic) igneous rock: formed from rapidly cooling lava on the Earth’s surface. Its fast cooling produces small crystals (fine-grained). Concept Tested: Granite (intrusive) and Basalt (extrusive) are both igneous rocks formed from magma/lava

NDA 2006-II

Q. 24. Sandstone is a:

(a) Extrusive igneous rock

(b) Intrusive igneous rock

(c) Metamorphic rock

(d) Sedimentary rock

Answer: (d) Sedimentary rock

Explanation: Sandstone is a clastic sedimentary rock formed by the compaction and cementation of sand-sized grains (quartz particles). It is one of the most common and widely distributed sedimentary rocks. It is not igneous (not formed from magma) nor metamorphic (not altered by heat and pressure from a parent rock). Concept Tested: Sandstone: clastic sedimentary rock formed by compacted and cemented sand grains

NDA 2006-I

Q. 25. Match List-I (Type of Rocks) with List-II (Example) and select the answer using the codes given below:

List I (Type of Rocks)	List II (Example)
A. Igneous Rocks	1. Basalt and Granite
B. Metamorphic Rocks	2. Limestone and Sandstone
C. Sedimentary Rocks	3. Marble and Quartzite

Codes:

(a) A-1, B-2, C-3

(b) A-1, B-3, C-2

(c) A-2, B-3, C-1

(d) A-3, B-1, C-2

Answer: (b) A-1, B-3, C-2

Explanation: Igneous Rocks (A) → Basalt and Granite (1). Basalt (extrusive) and Granite (intrusive) are both formed by the solidification of magma or lava. Metamorphic Rocks (B) → Marble and Quartzite (3). Marble is metamorphosed limestone; Quartzite is metamorphosed sandstone. Sedimentary Rocks (C) → Limestone and Sandstone (2). Both are formed by the deposition and compaction of sediments. Concept Tested: Rock type examples: Igneous (Basalt/Granite), Metamorphic (Marble/Quartzite), Sedimentary (Limestone/Sandstone)

★ JOVIK Exam Insight The three rock type groupings with key examples for NDA: Igneous: Granite (intrusive), Basalt (extrusive), Gabbro, Dolerite, Obsidian. Sedimentary: Sandstone, Limestone, Shale, Coal, Chalk, Conglomerate, Siltstone. Metamorphic: Marble (from limestone), Quartzite (from sandstone), Slate (from shale), Schist, Gneiss. Remember: metamorphic rocks are always derived FROM another rock (their parent/protolith).

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