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

# Short note: Granite

Engineering Geology I · Chapter 4: Petrology

- Asked in: 2068 Chaitra, 1 marks
- Video: [What is GRANITE ?](https://www.youtube.com/watch?v=_SkZTIrR0-U) — Let's Go Geo
- 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-granite
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-4

## Question

Write a short note on granite.

## Short answer

Granite is a light-coloured coarse-grained plutonic igneous rock with quartz, orthoclase feldspar, plagioclase, and mica or hornblende. Hard (Mohs 6-7), strong (100-250 MPa), low porosity. Used for foundations, dams, aggregate; joints and weathering are problems.

## Answer

**Granite** is a light-coloured, coarse grained plutonic igneous rock of acidic composition. It consists of quartz, orthoclase feldspar, plagioclase and mica or hornblende, in a holocrystalline granular texture. It is massive, hard (Mohs 6 - 7), strong (compressive strength 100 - 250 MPa) and has very low porosity. It is used for foundations, bridge piers, dams, facing stone, kerbs, aggregate and ballast. Weathering to clay and joints are its main engineering problems.

## Check yourself

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

1. Granite is which type of rock?
   A. Fine volcanic basic
   B. Clastic sedimentary
   C. Foliated metamorphic
   D. Coarse grained plutonic igneous, acidic
   Answer: D. It cooled slowly deep in the crust. (Key point: Granite type)

2. Which minerals mainly make granite?
   A. Quartz, feldspars and mica or hornblende
   B. Calcite and dolomite
   C. Olivine and pyroxene only
   D. Clay minerals
   Answer: A. These give acidic composition. (Key point: Granite minerals)

3. What are the main engineering problems of granite?
   A. Swelling
   B. Joints and weathering to clay
   C. Solubility
   D. Fissility
   Answer: B. Otherwise it is strong and hard. (Key point: Granite problems)