---
title: "Classification of minerals"
subject: "Engineering Geology I"
chapter: 3
key: "semester_3/engineering_geology_i:classification-of-minerals"
source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/classification-of-minerals
site: BCT Engineering
---

# Classification of minerals

Engineering Geology I · Chapter 3: Crystallography & Mineralogy

- Asked in: 2074 Asoj, 1.5 marks
- Video: [Mineral Groups](https://www.youtube.com/watch?v=8LoFxc_Txws) — Mike Sammartano
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/classification-of-minerals
- Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-3

## Question

How do you classify minerals?

## Short answer

Minerals are classified by abundance (rock-forming, accessory, ore), chemically (native elements, sulphides, oxides, silicates, etc.), and by colour (felsic light, mafic dark). Silicates are the largest group, about 90% of the crust.

## Answer

Minerals are classified in several ways.

**1. Based on abundance and role in rocks**
- **Rock-forming minerals**: abundant, form the bulk of rocks (quartz, feldspar, mica, amphibole, pyroxene, olivine, calcite).
- **Accessory minerals**: occur in small amounts (zircon, apatite, magnetite).
- **Ore minerals**: contain metals of economic value (galena, hematite, chalcopyrite).

**2. Chemical classification (most common)**
- Native elements (gold, graphite), sulphides (pyrite), oxides (hematite), halides (halite), carbonates (calcite), sulphates (gypsum), phosphates (apatite) and **silicates** (the largest group, about 90% of the crust).

**3. Colour-based**
- Felsic (light-coloured: quartz, feldspar) and mafic (dark: pyroxene, olivine, biotite).

## Check yourself

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

1. Minerals that occur in small amounts in rocks are called:
   A. Accessory minerals
   B. Rock-forming minerals
   C. Ore minerals
   D. Mafic minerals
   Answer: A. Examples: zircon, apatite, magnetite. (Key point: By role)

2. The largest chemical group of minerals is:
   A. Carbonates
   B. Silicates, about 90% of the crust
   C. Oxides
   D. Halides
   Answer: B. Silicates dominate the crust. (Key point: Chemical)

3. Which are mafic (dark) minerals?
   A. Quartz, feldspar
   B. Calcite, gypsum
   C. Pyroxene, olivine, biotite
   D. Halite, fluorite
   Answer: C. Quartz and feldspar are felsic. (Key point: Colour-based)

## Related in Engineering Geology I

- [Silicate versus carbonate minerals in the field](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Asilicate-versus-carbonate-minerals-in) — Engineering Geology I, chapter 3, asked 2×
- [Genetic classification of fault and joint](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Agenetic-classification-of-fault-and) — Engineering Geology I, chapter 5
- [Classification of sedimentary rocks](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aclassification-of-sedimentary-rocks) — Engineering Geology I, chapter 4, asked 4×
- [Fault: causes, classification, slope effects](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Afault-causes-classification-slope-effects) — Engineering Geology I, chapter 5

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