--- title: "Texture and properties of quartzite, limestone, granite" subject: "Engineering Geology I" chapter: 4 key: "semester_3/engineering_geology_i:texture-and-properties-of-quartzite" source: https://www.bctengineer.com/q/semester_3/engineering_geology_i/texture-and-properties-of-quartzite site: BCT Engineering --- # Texture and properties of quartzite, limestone, granite Engineering Geology I · Chapter 4: Petrology - Asked in: 2072 Chaitra, 6 marks - Video: [Rock ID With Willsey, Ep #14: Nonfoliated Rocks (Quartzite and Marble)](https://www.youtube.com/watch?v=Z2wTIggh1to) — Shawn Willsey: Geology Explained - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_3/engineering_geology_i/texture-and-properties-of-quartzite - Whole chapter: https://www.bctengineer.com/md/semester_3/engineering_geology_i/chapter-4 ## Question Describe the texture, structure, mineral composition and engineering properties of quartzite, limestone and granite. ## Short answer Quartzite is granoblastic, massive, >90% quartz, strength 150-300 MPa, very hard and durable, used as aggregate and foundation rock. Limestone is crystalline to clastic, bedded, calcite-rich, strength 50-150 MPa, soluble in acids, used for cement and building. Granite is holocrystalline, massive, with quartz, feldspar, mica, strength 100-250 MPa, low porosity, and used for dams and foundations. ## Answer #### Quartzite Metamorphic rock formed from sandstone by recrystallisation. - **Texture**: granoblastic (interlocking quartz grains), fine to medium grained; original grains fused with silica. - **Structure**: massive, non-foliated; sometimes relict bedding. - **Minerals**: more than 90 % quartz, with traces of mica, feldspar and iron oxides. - **Engineering properties**: compressive strength 150 - 300 MPa, specific gravity 2.65, very hard (Mohs 7), very low porosity, highly resistant to weathering and chemicals. Used as road metal, railway ballast, concrete aggregate and foundation rock. Very hard to dress, and it may show jointing and slip planes. #### Limestone Sedimentary rock formed by chemical or organic deposition of calcium carbonate. - **Texture**: crystalline, oolitic, fossiliferous or clastic (fine to coarse grains). - **Structure**: bedded, often jointed; may contain fossils and cavities. - **Minerals**: calcite (CaCO3), some dolomite, clay and silica as impurities. - **Engineering properties**: compressive strength 50 - 150 MPa, specific gravity 2.4 - 2.7, hardness 3, soluble in acidic water (sinkholes, caves, karst), effervesces with dilute HCl. Used for cement, lime, building stone and aggregate. Dam sites on limestone need grouting for solution cavities. #### Granite Plutonic igneous rock. - **Texture**: holocrystalline, phaneritic, medium to coarse granular (sometimes porphyritic). - **Structure**: massive, often with sheeting and joints; no bedding. - **Minerals**: quartz (20 - 40 %), orthoclase/microcline feldspar, plagioclase, biotite/muscovite or hornblende. - **Engineering properties**: compressive strength 100 - 250 MPa, specific gravity 2.6 - 2.8, hardness 6 - 7, water absorption below 0.5 %, excellent durability and polish. Used for foundations, piers, dams, facing, aggregate. Weathering can produce deep clay-rich residual soil, which must be removed from foundations. ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Quartzite is formed from A. limestone B. shale C. sandstone by recrystallisation D. basalt Answer: C. Over 90% quartz. (Key point: Quartzite) 2. Limestone consists mainly of A. quartz B. feldspar C. mica D. calcite Answer: D. Calcium carbonate. (Key point: Limestone mineral) 3. Weathered granite gives A. clay-rich residual soil to be removed from foundations B. sand only C. limestone D. slate Answer: A. Needs removal. (Key point: Granite soil) 4. Dam sites on limestone need A. no treatment B. grouting for solution cavities C. blasting only D. plastering Answer: B. Cavities cause leakage. (Key point: Limestone dam) ## Close variants set in other exams - [Texture and properties of four rocks](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Atexture-and-properties-of-four) — Engineering Geology I, chapter 4, asked 2× ## Related in Engineering Geology I - [Properties and uses of granite, phyllite, limestone](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aproperties-and-uses-of-granite) — Engineering Geology I, chapter 4, asked 4× - [Properties of granite, limestone, shale, marble](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aproperties-of-granite-limestone-shale) — Engineering Geology I, chapter 4 - [Properties of marble, slate, granite](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aproperties-of-marble-slate-granite) — Engineering Geology I, chapter 4, asked 2× - [Identify metamorphic rock; properties of sandstone and granite](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aidentify-metamorphic-rock-properties-of) — Engineering Geology I, chapter 4 - [Engineering significance of marble, granite, sandstone](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aengineering-significance-of-marble-granite) — Engineering Geology I, chapter 4 - [Engineering uses of granite and marble](https://www.bctengineer.com/question.md?key=semester_3%2Fengineering_geology_i%3Aengineering-uses-of-granite-and) — Engineering Geology I, chapter 4 ## Related in other subjects - [Fat lime composition, properties, uses](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Afat-lime-composition-properties-uses) — Civil Engineering Materials, chapter 4 - [Comment on cements from oxide composition](https://www.bctengineer.com/question.md?key=semester_5%2Fconcrete_technology_and_masonry_structure%3Acement-composition-comment) — Concrete Technology and Masonry Structure, chapter 1 - [Important properties of civil engineering materials](https://www.bctengineer.com/question.md?key=semester_3%2Fcivil_engineering_materials%3Aimportant-properties-civil-materials) — Civil Engineering Materials, chapter 1, asked 8× - [Structure, processing, properties and selection](https://www.bctengineer.com/question.md?key=semester_3%2Fmaterial_science%3Astructure-processing-properties-selection) — Material Science, chapter 1