In construction, choosing the right building material is vital for durability, cost-efficiency, and appearance. Among the wide range of natural stones available, granite and basalt stand out for their strength and versatility. Though both are igneous rocks, they have different characteristics that influence their usage in construction. Let us explore their properties, advantages, disadvantages, and real-life applications.
What is Granite?
Granite is an intrusive igneous rock formed by the slow cooling of magma deep within the Earth. It is mainly composed of quartz, feldspar, and mica, giving it a coarse-grained texture. In India, granite is abundantly found in Tamil Nadu, Karnataka, Andhra Pradesh, and Rajasthan.
Properties of Granite
- Texture: Coarse-grained
- Colour: Varies – white, pink, red, grey, and black
- Compressive strength: 100–250 MPa
- Water absorption: Low
- Durability: Excellent
- Weather resistance: High
Advantages of Granite
- Visually attractive and available in multiple colours
- Resistant to weathering and chemical attack
- Highly durable and long-lasting
- Can be polished for decorative uses
- Adds property value due to premium look
Disadvantages of Granite
- Expensive compared to other stones
- Heavier, making handling and transport difficult
- Requires skilled labour for installation
- Can crack under rapid temperature changes
Applications of Granite
- Kitchen countertops and vanity tops
- Floor tiles and wall cladding
- Staircases and paving stones
- Monuments and memorials
- Window sills and arches
Famous Indian Monuments Made of Granite
- Brihadeeswarar Temple, Thanjavur – Entirely built using granite
- Vittala Temple, Hampi – Includes intricate granite stonework
- Shore Temple, Mahabalipuram – An example of granite in coastal construction
What is Basalt?
Basalt is an extrusive igneous rock formed by the rapid cooling of lava on the Earth’s surface. It is typically dark grey or black in colour and has a fine-grained texture. Basalt is widely available in Maharashtra, Madhya Pradesh, and across the Deccan Plateau.
Properties of Basalt
- Texture: Fine-grained
- Colour: Dark grey to black
- Compressive strength: 100–300 MPa
- Density: High
- Porosity: Low
- Thermal resistance: High
Advantages of Basalt
- Extremely strong and durable
- Less costly than granite
- Excellent thermal insulation properties
- Resistant to wear and heavy loads
- Suitable for large-scale civil works
Disadvantages of Basalt
- Lacks aesthetic variety compared to granite
- Difficult to polish due to fine grain
- Limited decorative applications
- Heavier tools required for cutting and shaping
Applications of Basalt
- Road base and highway construction
- Railway ballast
- Concrete aggregate
- Building blocks and kerbstones
- Industrial flooring
Famous Indian Structures Using Basalt
- Gateway of India, Mumbai – Built using yellow basalt and reinforced concrete
- Elephanta Caves, Mumbai Harbour – Carved into basalt rock
- Daulatabad Fort, Maharashtra – Constructed using locally available basalt
Which is Stronger – Granite or Basalt?
While both are very strong stones, basalt has a slightly higher compressive strength, ranging from 100 to 300 MPa, compared to granite’s 100 to 250 MPa. This makes basalt more suitable for heavy-duty applications like road construction, while granite is favoured for both structural and decorative purposes.
Which Cools Faster – Basalt or Granite?
Basalt cools faster because it forms on the Earth’s surface. The rapid cooling gives it a fine-grained texture. Granite, however, cools slowly beneath the surface, allowing larger crystals to form. This slow process gives granite its speckled, coarse appearance and ability to be polished.
Is Basalt Cheaper than Granite?
Yes, basalt is generally cheaper. Quarrying and processing granite involve more effort due to its depth, hardness, and demand in decorative architecture. In India, granite can cost ₹100–₹300 per sq. ft or more, whereas basalt is more affordable and widely used in bulk for infrastructure projects.
Key Differences at a Glance
| Feature | Granite | Basalt |
|---|---|---|
| Formation | Intrusive (slow cooling) | Extrusive (rapid cooling) |
| Texture | Coarse-grained | Fine-grained |
| Appearance | Varied colours, decorative | Uniform dark colour |
| Compressive Strength | 100–250 MPa | 100–300 MPa |
| Cost | Higher | Lower |
| Uses | Decorative and structural | Heavy-duty infrastructure |
Relevant IS Codes for Granite and Basalt in Construction (India)
1. IS 1121 (Part 1 to 4): 1974
Title: Methods of Test for Determination of Strength Properties of Natural Building Stones
Use: Specifies methods to test compressive strength, transverse strength, and other mechanical properties for stones like granite and basalt.
2. IS 1122: 1974
Title: Method of Test for Determination of True Specific Gravity of Natural Building Stones
Use: Important for calculating density and weight of granite or basalt when used in structures.
3. IS 1123: 1975
Title: Method of Identification of Natural Building Stones
Use: Helps in identifying various natural stones including granite and basalt through petrographic and field analysis.
4. IS 1597 (Part 1): 1992
Title: Construction of Stone Masonry – Code of Practice
Use: Offers guidelines for using stones like granite and basalt in masonry construction.
5. IS 1805: 1973
Title: Glossary of Terms Relating to Building Stones
Use: Provides standardised terminology for various types of stones used in construction.
6. IS 3316: 1974
Title: Specification for Structural Granite
Use: Specific to granite, it defines physical and mechanical property requirements for structural-grade granite used in buildings, monuments, and bridges.
7. IS 3622: 1988
Title: Specification for Sandstone (Building Stones)
Note: While for sandstone, it may be cross-referenced in broader natural stone applications.
Conclusion🎯
Both granite and basalt serve unique purposes in modern construction. Granite, with its stunning appearance and solid structure, is perfect for interiors, monuments, and detailed stonework. Basalt, being more cost-effective and strong, is best suited for infrastructure and large-scale engineering works.
When choosing between the two, consider your budget, desired appearance, and intended use. Understanding their properties will help you select the right stone for lasting value and performance.
Frequently Asked Questions (FAQs)
1. Which is stronger – granite or basalt?
Basalt is generally stronger than granite in terms of compressive strength. While granite has a compressive strength of about 100–250 MPa, basalt can reach up to 300 MPa. This makes basalt more suitable for heavy-load applications like roads and pavements.
2. Is basalt cheaper than granite?
Yes, basalt is usually more affordable than granite. Since basalt is widely available and used in bulk for infrastructure works, its cost per unit is lower. Granite, on the other hand, is costlier due to its decorative value and processing requirements.
3. Which cools faster – basalt or granite?
Basalt cools faster because it forms on the Earth’s surface from lava, making it a fine-grained rock. Granite cools slowly deep underground, resulting in a coarse-grained texture with larger mineral crystals.
4. Where is granite commonly used in construction?
Granite is used for flooring, kitchen countertops, wall cladding, stairs, and decorative elements. It is favoured in residential and commercial construction for its beauty, strength, and durability.
5. What are the common uses of basalt in India?
Basalt is mainly used in road construction, railway ballast, building blocks, and concrete aggregate. Its strength and thermal resistance make it ideal for large-scale civil engineering projects across India.
6. Are there any famous monuments made from granite and basalt in India?
Yes. Notable granite monuments include the Brihadeeswarar Temple (Thanjavur) and the Shore Temple (Mahabalipuram). Basalt was used to build structures like the Gateway of India (Mumbai) and the Elephanta Caves.