---
title: "Short note: Quartzite"
subject: "Engineering Geology I"
chapter: 4
key: "semester_3/engineering_geology_i:short-note-quartzite"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/short-note-quartzite
site: BCT Engineering
---

# Short note: Quartzite

Engineering Geology I · Chapter 4: Petrology

- Asked in: 2066 Jestha (old course), 4 marks
- Video: [All about Quartzite Rocks](https://www.youtube.com/watch?v=PrXa-SkFheU) — NoNa TV
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/short-note-quartzite
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-4

## Question

Write a short note on quartzite.

## Short answer

Quartzite is a hard non-foliated metamorphic rock from recrystallized quartz sandstone, over 90% quartz, granoblastic texture. Very hard (Mohs 7), specific gravity 2.65, strength 150-300 MPa, resists weathering. Used as aggregate, ballast, riprap; found in Himalayan Nepal.

## Answer

**Quartzite** is a hard, non-foliated metamorphic rock formed by recrystallisation of quartz sandstone under heat and pressure (contact or regional metamorphism).

- **Texture and structure**: granoblastic texture, with quartz grains fused into an interlocking mosaic; massive; relict bedding may remain.
- **Composition**: over 90 % quartz, with small amounts of mica, feldspar and iron oxides.
- **Properties**: colour white, grey, pink or brown; very hard (Mohs 7); specific gravity 2.65; compressive strength 150 - 300 MPa; very low porosity; fractures across grains (conchoidal); resists weathering and chemicals.
- **Engineering uses**: road metal, concrete aggregate, railway ballast, riprap, and a good foundation rock for dams and bridges. It is hard to excavate and dress and is generally jointed, so joints control seepage and stability.
- **Occurrence**: found in the Lesser and Higher Himalaya of Nepal, such as in the Nawakot Complex.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. How is quartzite formed?
   A. Metamorphism of limestone
   B. Cooling of magma
   C. Recrystallisation of quartz sandstone by metamorphism
   D. Compaction of clay
   Answer: C. Heat and pressure fuse quartz grains. (Key point: Quartzite origin)

2. Which texture and structure are typical?
   A. Lepidoblastic, foliated
   B. Vesicular, flow banded
   C. Pelitic, laminated
   D. Granoblastic, massive, non-foliated
   Answer: D. Interlocking quartz mosaic gives massive rock. (Key point: Quartzite texture)

3. What is the main mineral and approximate content?
   A. Quartz, over 90 %
   B. Calcite, over 90 %
   C. Mica, over 50 %
   D. Feldspar, over 70 %
   Answer: A. Parent sandstone is mainly quartz. (Key point: Quartzite composition)

4. Why is quartzite a good aggregate and foundation rock, yet difficult to work?
   A. Soft and easily cut
   B. Very hard (Mohs 7), strong and weather resistant, but hard to excavate and jointed
   C. Highly soluble
   D. Weak along cleavage
   Answer: B. Joints control seepage and stability. (Key point: Engineering use)