BGYCT 133 key facts: June 2026
- Course code: BGYCT 133 (printed BGYCT-133)
- Subject: Crystallography, Mineralogy and Economic Geology
- Programme: Bachelor of Science (General), BSCG, Geology discipline, Semester II; also Bachelor of Science (Multidisciplinary), BSCM
- Credits: 4 (theory); the 2-credit lab is a separate course, BGYCL-134
- Blocks and units: 4 blocks, 15 units, in 2 volumes
- Maximum marks: 50
- Duration: 2 hours
- Questions in the paper: 4 compulsory questions containing 19 question items; printed code C-3854
- Assignment weightage: 30 per cent of the course result
- Samples shown on this page: 2 (Q2(e) and Q3(b)); all 19 in the paid file
BGYCT 133 Solved Question Paper for the June 2026 term-end exam gives you exam-length answers to every question IGNOU set this session, from the Nicol prism and nesosilicates to bauxite and placer deposits. Two answers are open below, so you can judge the depth and the diagrams before you message us.
1. What the June 2026 Solved Paper Includes
BGYCT 133 is a 4-credit theory course in the second semester of the Geology discipline of IGNOU's Bachelor of Science (General), also studied in the BSCM programme.
The June 2026 paper had four compulsory questions for 50 marks in two hours. Inside them sit 19 separate question items: Q1 offers seven 2-mark parts, Q2 six short notes, Q3 two long options and Q4 two sets of paired 5-mark parts.
Our solved file answers all 19 items, including the alternatives you are not required to attempt. That choice matters here, because a student strong in crystallography may prefer Q3(a) on symmetry, while one who revised Block 4 will pick Q3(b) on magmatic ore formation.
The paper leans on Block 4 this session. Wall rock alteration, iron ores, fertiliser minerals, coal ranks, placers and bauxite together carry more choices than crystallography, so the economic geology answers in our file get Indian deposit names, not only textbook definitions.
If you are collecting papers for every second-semester science course, our BSCG Question Paper pages follow the same format.
2. Two Answers Solved in Full, Seventeen Held Back
Two BGYCT 133 answers are shown in full below, Q2(e) on ranks of coal and Q3(b) on early and late magmatic concentration; the other 17 answers are in the paid file.
Both questions are reproduced with the paper's own numbering and wording. The answers were written by our team to the length the marks call for.
Ranks of coal
Question 2 (e): Write a short note on the ranks of coal. (5)
Rank of coal is the degree of coalification a coal has reached, that is, how far the original plant matter has been altered from peat towards anthracite by burial depth, temperature, pressure and time. As rank rises, carbon content, hardness and lustre increase, while moisture, oxygen and volatile matter fall.
Coalification works in two stages. In the biochemical stage, plant debris in swamps decays under waterlogged, oxygen-poor conditions and becomes peat. In the geochemical stage, buried peat is heated and compressed, which drives off water, carbon dioxide and methane and steadily raises the proportion of carbon.
| Rank | Approximate carbon | Distinguishing features |
|---|---|---|
| Peat | about 55 to 60% | Brown, fibrous, plant remains visible; very high moisture; the starting stage, not a true coal |
| Lignite (brown coal) | about 60 to 70% | Soft, brown to black, woody texture; high moisture, crumbles on drying; low heat value |
| Sub-bituminous | about 70 to 76% | Dull black, less moisture than lignite; transitional stage between brown and black coal |
| Bituminous | about 76 to 90% | Black, banded, burns with a smoky yellow flame; includes coking coals used for metallurgical coke |
| Anthracite | above 90% | Hard, jet black, sub-metallic lustre, conchoidal fracture; burns with a short blue, nearly smokeless flame |
Indian examples help in this note. Lignite comes mainly from Tertiary basins at Neyveli in Tamil Nadu, Barmer in Rajasthan and Kutch in Gujarat. Most bituminous coal comes from Gondwana basins of the Damodar valley, such as Jharia, Raniganj and Bokaro. Anthracite is scarce in India; semi-anthracite to anthracite occurs in the Jammu region, where Himalayan tectonics raised the rank.
Rank generally increases with depth of burial, an observation known as Hilt's law, because deeper seams experienced higher temperatures. In the laboratory, rank is judged from proximate analysis (moisture, volatile matter, fixed carbon) and, more precisely, from vitrinite reflectance, which rises steadily from lignite to anthracite.
Early and late magmatic concentration processes of ore formation
Question 3 (b): Discuss the early and late magmatic concentration processes of ore formation. (10)
Magmatic concentration is the process by which valuable minerals crystallise directly from a cooling magma and become concentrated inside the igneous body itself. Following Bateman's classification, these deposits are divided into early magmatic and late magmatic types, depending on whether the ore minerals crystallised before or after most of the rock-forming silicates.
A. Early magmatic processes
Here the ore minerals are among the first to crystallise. Chromite, diamond and some platinum-group minerals behave this way because they form at high temperature from ultrabasic and basic magma. The early crystals are then left scattered, settled into layers or squeezed out with the magma, giving three processes.
- Dissemination. The ore mineral crystallises in place and stays scattered through the host rock without further concentration. Diamonds in kimberlite pipes are the classic case, such as the Kimberley pipes of South Africa and the Majhgawan pipe near Panna in Madhya Pradesh. Such deposits are worked only because the mineral is very valuable.
- Segregation. Heavy early crystals sink through the still-liquid magma under gravity and collect near the floor of the intrusion as bands or seams. The result is a layered ore body parallel to the igneous layering. Chromite seams of the Bushveld Complex in South Africa and of the Great Dyke of Zimbabwe are standard examples.
- Injection. If the crystal mush rich in early ore minerals is disturbed by earth movements before it solidifies, it may be squeezed into fractures in the parent rock or the wall rocks. This gives dyke-like or lens-shaped ore bodies with sharp contacts. Some chromite bodies in ultrabasic intrusions are explained this way.
B. Late magmatic processes
These ores form from the residual magma left after most silicates have crystallised. Iron, titanium, phosphorus, sulphur and volatiles become concentrated in this residual liquid, so the ore minerals crystallise late. In thin section they fill spaces between, or corrode, the earlier silicate grains. Four processes are recognised.
- Residual liquid segregation. The iron-rich residual liquid is trapped among the silicate crystals and crystallises where it is, producing layers or patches of titaniferous and vanadiferous magnetite. The magnetite layers in the upper part of the Bushveld Complex and the vanadiferous titanomagnetite of Mayurbhanj district in Odisha are examples.
- Residual liquid injection. The residual liquid is filter-pressed out of the crystal mush and injected into fractures, either within the parent body or in the surrounding rocks, forming dykes, veins and irregular masses. The magnetite-apatite ores of Kiruna in Sweden and the titaniferous magnetite of the Adirondacks in the USA are classic examples.
- Immiscible liquid segregation. In a sulphur-rich basic magma, a sulphide liquid separates from the silicate liquid, much as oil separates from water. Being denser, the sulphide droplets sink and collect at the base of the intrusion, giving copper-nickel ores of pyrrhotite, pentlandite and chalcopyrite. The Insizwa deposit of South Africa and the basal ores of Sudbury in Canada are often cited.
- Immiscible liquid injection. If the sulphide liquid is disturbed before it solidifies, it can be injected into fractures in the host or nearby rocks, forming sulphide dykes and veins. The offset dykes that carry part of the Sudbury ore are explained in this way.
| Point | Early magmatic | Late magmatic |
|---|---|---|
| Time of ore crystallisation | Before or with the first silicates | After most silicates, from residual liquid |
| Typical ores | Chromite, diamond, platinum-group minerals | Titaniferous magnetite, magnetite-apatite, Cu-Ni sulphides |
| Processes | Dissemination, segregation, injection | Residual liquid and immiscible liquid segregation or injection |
| Texture | Well-formed ore crystals enclosed by silicates | Ore minerals fill gaps between or corrode earlier silicates |
Diagrams to draw. Two sketches finish this answer. First, a crystal settling diagram for segregation: a cross-section of a magma chamber with heavy dark ore crystals shown sinking through the liquid and collecting as a banded layer along the floor, labelled magma, settling crystals and chromite seam. Second, a filter-pressing diagram for injection: a partly solidified intrusion with arrows showing residual liquid being squeezed out of the crystal mush into a fracture, labelled crystal mush, residual liquid and ore dyke. The full file carries both as labelled figures.
Both groups are endogenous processes tied to basic and ultrabasic magmas, and together they supply much of the world's chromium, nickel, platinum, vanadium and titanium.
3. Questions Answered Only in the Full File
The other 17 question items from the June 2026 paper are listed below exactly as printed. Their answers are not shown on this page.
Question 1 (answer any five, 2 marks each):
(a) What is a Nicol prism?
(b) What is the chemical composition of quartz and its hardness on Mohs' hardness scale?
(c) Define nesosilicates.
(d) What are allochromatic minerals?
(e) Differentiate between crystallographic and geometric symmetry.
(f) Define pleochroism.
(g) Give two optical properties of calcite.
Question 2 (write short notes on any four, 5 marks each):
(a) Forms present in the orthorhombic system
(b) Wall rock alteration
(c) Process of formation of iron ores
(d) Uses of minerals in the fertiliser industry
(f) Methods of determining specific gravity
Question 3 (a): Define crystallographic axes. Discuss the three elements of symmetry with the help of diagrams. (10)
Question 4 (a): Discuss the habits of crystal aggregates with suitable examples. (5)
Question 4 (b): What are placer deposits? Discuss the types of placer deposits according to the mode of origin. (5)
Question 4 Or (a): Discuss the processes of formation of bauxite deposits and their distribution in India. (5)
Question 4 Or (b): Discuss the different kinds of non-metallic lustres with examples. (5)
4. Syllabus by Block and Unit
BGYCT 133 has 4 blocks and 15 units in two volumes: Volume 1 holds crystallography and mineralogy, and Volume 2 holds optical mineralogy and economic geology.
The table below follows the IGNOU self-learning material. The topics in each row are the ones IGNOU papers have actually drawn from, so you can see where each June 2026 question sits.
| Block | Unit | Key topics |
|---|---|---|
| Block 1: Basic Concepts of Crystallography | Unit 1: Crystal Properties | Crystal faces, edges and solid angles; interfacial angle and Steno's law; crystal habit |
| Block 1: Basic Concepts of Crystallography | Unit 2: Crystal Symmetry | Plane, axis and centre of symmetry; crystallographic versus geometric symmetry |
| Block 1: Basic Concepts of Crystallography | Unit 3: Crystal Systems | Crystallographic axes and axial ratios; normal-class forms of the cubic, tetragonal, orthorhombic and hexagonal systems |
| Block 2: Mineralogy | Unit 4: Minerals | Colour, streak and lustre; hardness on the Mohs scale; specific gravity |
| Block 2: Mineralogy | Unit 5: Classification of Minerals | Chemical classes of minerals; silicate structures from nesosilicates to tectosilicates |
| Block 2: Mineralogy | Units 6 and 7: Rock-Forming Minerals | Physical properties of quartz, feldspars, micas, pyroxenes, amphiboles, olivine and garnet |
| Block 3: Optical Mineralogy | Unit 8: Polarising Microscope | Parts of the microscope; polariser, analyser and the Nicol prism; orthoscopic illumination |
| Block 3: Optical Mineralogy | Unit 9: Optical Properties of Minerals | Relief and pleochroism in plane polarised light; interference colours, extinction and twinning under crossed nicols |
| Block 3: Optical Mineralogy | Unit 10: Optical Properties of Rock-Forming Minerals | Thin-section identification of quartz, olivine, augite, hornblende, biotite and calcite |
| Block 4: Economic Geology | Unit 11: Ore and Ore Deposits | Ore, gangue, tenor and ore grade; concordant and discordant ore bodies; Clarke values |
| Block 4: Economic Geology | Unit 12: Processes of Ore Formation | Magmatic concentration; hydrothermal and contact metasomatic processes; residual and mechanical (placer) concentration |
| Block 4: Economic Geology | Unit 13: Metallic Minerals | Ores, genesis and Indian distribution of iron, copper, aluminium (bauxite) and lead-zinc |
| Block 4: Economic Geology | Unit 14: Non-Metallic Minerals | Minerals for the refractory, abrasive, fertiliser and building industries; mica and gypsum |
| Block 4: Economic Geology | Unit 15: Coal and Petroleum | Origin, constitution and ranks of coal; Gondwana and Tertiary coalfields; origin and traps of petroleum |
The official block PDFs, in English and Hindi, are on IGNOU's eGyanKosh page for BGYCT-133. Units 11 to 15 are worth extra time, since this session drew seven of its 19 items from Block 4.
For unit-wise notes written in the same style as these answers, see our BGYCT 133 Study Material, which follows this block order.
5. Question Paper Pattern and Marks
The June 2026 paper carried 50 marks for 2 hours across four compulsory questions, each with an internal choice.
| Question | Format and choice | Marks | June 2026 focus |
|---|---|---|---|
| Q1 | Any 5 of 7 brief answers | 5 × 2 = 10 | Nicol prism, quartz, nesosilicates, pleochroism, calcite optics |
| Q2 | Any 4 of 6 short notes | 4 × 5 = 20 | Orthorhombic forms, wall rock alteration, iron ores, coal ranks |
| Q3 | Any 1 of 2 long answers | 1 × 10 = 10 | Symmetry elements with diagrams, or magmatic concentration |
| Q4 | One set of two 5-mark parts, (a) and (b), or the alternative set | 2 × 5 = 10 | Crystal aggregates and placers, or bauxite and non-metallic lustre |
This shape has stayed steady in recent sessions, though the number of options in Q1 and Q2 changes. The December 2025 paper also offered seven brief answers and six notes, while June 2025 offered ten and eight.
The term-end exam is one part of your result. The IGNOU assignment booklet for this course gives a 30 per cent weightage to the tutor-marked assignment, so the theory paper decides the larger share.
Reading the question paper next to older ones shows how often the same mineral or ore returns. Our IGNOU Previous Year Question Paper section keeps those sessions together for practice.
6. Topics That Keep Returning Since June 2022
Crystal systems, coal and the uses of minerals appeared in all eight official BGYCT 133 papers from June 2022 to December 2025, while specific gravity had not appeared once before June 2026.
We checked each topic of the June 2026 paper against the eight earlier papers published by IGNOU: June 2022, December 2022, June 2023, December 2023, June 2024, December 2024, June 2025 and December 2025. Counts show in how many of those eight sessions the topic was asked.
| Topic | June 2026 item | Earlier sessions where asked | Count (of 8) |
|---|---|---|---|
| Axes, symmetry and forms of crystal systems | Q1(e), Q2(a), Q3(a) | Every session; cubic, tetragonal, orthorhombic and hexagonal systems rotate, plus beryl, baryte, galena and zircon | 8 |
| Coal: origin, constitution, ranks, distribution | Q2(e) (Sample 1) | Every session; ranks or grades specifically in Jun 2023, Dec 2023 and Dec 2024 | 8 |
| Industrial and strategic uses of minerals | Q2(d) | Every session; refractory, abrasive, building and war uses, but never fertiliser before June 2026 | 8 |
| Silicate structures and rock-forming silicate groups | Q1(c) | Jun 2022, Dec 2022, Jun 2023, Dec 2023, Dec 2024, Jun 2025 | 6 |
| Ores and formation of iron | Q2(c) | Dec 2022, Jun 2024, Dec 2024, Jun 2025, Dec 2025 | 5 |
| Colour of minerals, idiochromatic and allochromatic | Q1(d) | Dec 2022, Jun 2025 (streak and colour), Dec 2025 | 3 |
| Pleochroism and pleochroic haloes | Q1(f) | Dec 2022, Jun 2023, Dec 2023 | 3 |
| Physical or optical properties of calcite | Q1(g) | Jun 2022, Jun 2023, Jun 2025 | 3 |
| Polarising microscope and Nicol prism | Q1(a) | Jun 2022, Dec 2024, Jun 2025 | 3 |
| Crystal habit and crystal aggregates | Q4(a) | Jun 2022, Dec 2022, Dec 2025 | 3 |
| Magmatic concentration | Q3(b) (Sample 2) | Dec 2024 (printed as magnetic concentration), Dec 2025 (late magmatic process) | 2 |
| Placers and mechanical concentration | Q4(b) | Jun 2023, Dec 2023 | 2 |
| Lustre of minerals | Q4 Or (b) | Jun 2023, Jun 2024 | 2 |
| Hardness and the Mohs scale | Q1(b) | Jun 2022 (kyanite), Dec 2024 | 2 |
| Aluminium ores and bauxite | Q4 Or (a) | Jun 2023 | 1 |
| Wall rock alteration | Q2(b) | Jun 2025 (printed as wall rock alternation) | 1 |
| Specific gravity determination | Q2(f) | — | 0 |
The pattern is clear. Crystallography and coal are safe bets every session, but short-answer topics such as pleochroism and calcite rotate. For a ranked list of likely areas before December 2026, see our IGNOU Solved Guess Paper page.
7. How Our Answers Are Written and Checked
Every BGYCT 133 answer is written from the IGNOU self-learning material, sized to the printed marks and checked by a second reviewer before the file is released.
Our team drafts each answer after working through the earlier BGYCT 133 papers listed above, so recurring areas such as crystal systems and coal get the fuller treatment examiners have rewarded.
Length follows marks. A 2-mark item gets a precise definition and one example, a 5-mark note about 250 to 300 words, and a 10-mark answer about 500 to 650 words. Crystallography and ore-formation answers carry labelled sketches, because the paper asks for well labelled diagrams.
Economic geology answers name real Indian deposits, such as Neyveli lignite, Jharia coal and Mayurbhanj magnetite, since examiners mark down answers that stop at definitions.
8. Solved File Index of All 19 Question Items
The full file answers all 19 question items; 2 are open on this page and 17 are in the full file only.
BGYCT 133 is a theory course, so this index replaces a practical file index. Lab work for this subject is assessed in the separate course BGYCL-134, and its record is not part of this file. The unit tags below are our own mapping to the study material.
| Item | Topic | Block and unit | Where the answer is |
|---|---|---|---|
| Q1(a) | Nicol prism | Block 3, Unit 8 | Full file |
| Q1(b) | Composition and hardness of quartz | Block 2, Units 4, 6 and 7 | Full file |
| Q1(c) | Nesosilicates | Block 2, Unit 5 | Full file |
| Q1(d) | Allochromatic minerals | Block 2, Unit 4 | Full file |
| Q1(e) | Crystallographic versus geometric symmetry | Block 1, Unit 2 | Full file |
| Q1(f) | Pleochroism | Block 3, Unit 9 | Full file |
| Q1(g) | Two optical properties of calcite | Block 3, Unit 10 | Full file |
| Q2(a) | Forms in the orthorhombic system | Block 1, Unit 3 | Full file |
| Q2(b) | Wall rock alteration | Block 4, Units 11 and 12 | Full file |
| Q2(c) | Formation of iron ores | Block 4, Unit 13 | Full file |
| Q2(d) | Minerals in the fertiliser industry | Block 4, Unit 14 | Full file |
| Q2(e) | Ranks of coal | Block 4, Unit 15 | Sample 1 above |
| Q2(f) | Methods of determining specific gravity | Block 2, Unit 4 | Full file |
| Q3(a) | Crystallographic axes and three symmetry elements | Block 1, Units 2 and 3 | Full file |
| Q3(b) | Early and late magmatic concentration | Block 4, Unit 12 | Sample 2 above |
| Q4(a) | Habits of crystal aggregates | Blocks 1 and 2, Units 1 and 4 | Full file |
| Q4(b) | Placer deposits and their types | Block 4, Unit 12 | Full file |
| Q4 Or (a) | Bauxite formation and Indian distribution | Block 4, Unit 13 | Full file |
| Q4 Or (b) | Non-metallic lustres | Block 2, Unit 4 | Full file |
9. Programmes That Include BGYCT 133
BGYCT 133 is studied in two IGNOU programmes: the Bachelor of Science (General), BSCG, and the Bachelor of Science (Multidisciplinary), BSCM.
In the Bachelor of Science (General), BGYCT 133 is the second-semester theory course of the Geology discipline. It follows BGYCT-131 Physical and Structural Geology and sets up BGYCT-135 Petrology, where the optical mineralogy you learn here is used to identify rocks in thin section.
BSCM students take the same paper, and the June 2026 paper was printed for both programmes together. The questions, marks and solved file are therefore identical for both groups.
10. How to Get the Full Solved Question Paper
Message us on WhatsApp at 9899436384 to get the complete file with answers to all 19 question items of the June 2026 paper.
The file is shared as a PDF. It contains the 2 answers shown above plus the 17 answers that are not on this page, each tagged with its block and unit.
- Save 9899436384 and open WhatsApp.
- Send the course code BGYCT 133 and the session June 2026.
- Our team replies with the price and payment details.
- After payment, the solved PDF is sent to the same chat.
11. BGYCT 133 FAQs
These answers cover the June 2026 file, the exam pattern and how to order on WhatsApp.
Which questions are solved in full on this page?
Two questions are solved in full on this page: Q2(e) on ranks of coal, a 5-mark short note, and Q3(b) on early and late magmatic concentration, a 10-mark long answer. The remaining 17 question items of the June 2026 paper are listed by their printed wording only. Their answers, diagrams and examples are kept in the complete solved file, which we share on WhatsApp.
How do I get the full June 2026 solved file on WhatsApp?
Send a WhatsApp message to 9899436384 with the course code BGYCT 133 and the session June 2026. Our team replies with the price and payment details, and the PDF is shared after payment. The file contains answers to all 19 question items of the paper, which means the 2 answers shown here plus the 17 that appear only in the full file.
How many credits and blocks does BGYCT 133 carry?
BGYCT 133 is a 4-credit theory course listed in the second semester of the BSCG Geology discipline. Its study material has 4 blocks in 2 volumes: Basic Concepts of Crystallography, Mineralogy, Optical Mineralogy and Economic Geology, spread over 15 units. The 2-credit laboratory course, BGYCL-134, is separate and has its own practical assessment, so it is not part of this paper.
What is the exam pattern in the June 2026 paper?
The June 2026 paper carried 50 marks for 2 hours. Q1 asked for any five of seven 2-mark answers, Q2 for any four of six 5-mark notes, and Q3 for one of two 10-mark questions. Q4 gave a choice between two sets, each made of two 5-mark parts. All four questions were compulsory, and labelled diagrams were expected wherever they fit.
Which BGYCT 133 topics repeat most often in IGNOU papers?
Across the eight official papers from June 2022 to December 2025, BGYCT 133 asked on crystal systems, coal and the uses of minerals in every single session. Silicate structures appeared in six sessions and iron ores in five. Pleochroism, mineral colour, calcite and crystal habit each appeared three times. Specific gravity, asked in June 2026, had not appeared in any of those eight papers.
Does the solved file include practical or lab record work?
No. BGYCT 133 is examined as a theory paper, and the practical work belongs to its companion lab course, BGYCL-134 Crystallography, Mineralogy and Economic Geology: Laboratory. This solved file covers only the 19 question items of the June 2026 term-end paper. It maps each answer to its block and unit, but it is not a practical record.
Are the answers written to the length IGNOU expects?
Yes. Each answer follows the marks printed against it. A 2-mark item gets a precise definition with one example, a 5-mark note runs to roughly 250 to 300 words, and a 10-mark answer to about 500 to 650 words. Crystallography and ore-formation answers add labelled sketches, because the paper instructs students to draw well labelled diagrams.
Who writes and reviews the solved answers?
The answers are written by our subject team led by Prateek Talwar and reviewed by Sheetal Kirola before release. The review checks each answer against the IGNOU self-learning material, checks Indian deposit names and locations, and confirms the answer length against the marks.
12. Who Wrote and Checked the BGYCT 133 Answers
The BGYCT 133 answers were written by the Unnati Educations geology team and reviewed by Sheetal Kirola.
Prateek Talwar, founder of Unnati Educations, leads the IGNOU science solved-paper series and prepares answers from the course blocks and the official term-end paper. Sheetal Kirola, Academic Head (M.Ed.), checks every mineral name, deposit location and diagram label against the BGYCT-133 blocks before release.