What Are the Uses of Rocks? Class 7 Complete Answer

This topic comes from Chapter 2: Inside Our Earth of the NCERT Class 7 Geography textbook (Our Environment). Understanding the uses of rocks is an important part of this chapter and frequently appears in school exams in both short-answer and fill-in-the-blank formats. Before understanding what are the uses of rocks Class 7, it is important to know what a rock is.

What Is a Rock?

A rock is a natural substance made up of one or more minerals that forms the Earth’s crust. In simple terms, rocks are solid materials found on the Earth’s surface and inside it. They can be of different types, shapes, and sizes. Granite, a common rock, is a combination of the minerals quartz, feldspar, and biotite. Rocks are made up of one or more minerals and come in three main types: igneous, sedimentary, and metamorphic.

What Are the Uses of Rocks: Class 7 Short Answer

Rocks are very useful in our daily lives because they provide materials for construction, energy, and many useful products. They are used in many ways:

Building materials: Rocks like granite and marble are used to construct houses, roads, bridges, and buildings.
Source of minerals: Rocks contain important minerals like iron, gold, and copper, which are used in making tools and machines.
Making cement: Limestone is used to make cement for construction.
Fuel: Some rocks, like coal, are used as fuels for energy.
Decorative purposes: Precious stones and marble are used for jewellery and decoration.

What Are the Uses of Rocks: Class 7 Long Answer

Houses and buildings are built of rocks such as stones, slats, granite, and marble. Rocks are the most basic and widely used building material in the world. The Taj Mahal is made of white marble (a type of metamorphic rock), while the Red Fort of Delhi is made of red sandstone (a type of sedimentary rock). These are famous examples of how rocks have shaped India's greatest monuments.

Making Roads, Bridges, and Embankments

Rocks (stones and slats) are used in building bridges and embankments. Hard rocks are also used to make railway tracks and road foundations because of their strength and durability.

Making Grinding Stones and Statues

Hard rocks are used for making roads, houses, factories, and structures. Red sandstone and marble are commonly used for construction. Many utility objects, such as statues and grinding stones, are commonly made from rocks. Silouta or Sil-batta (a grinding stone found in every Indian kitchen) is usually made of granite, which is a type of igneous rock.

As Gemstones

Some precious rocks are used as gemstones. Diamonds, rubies, sapphires, and emeralds are all formed within rocks and are extracted and polished for use in jewellery.

As Fuels in Industries

The minerals that make up rocks are used as fuels, medicines, fertilisers, and in various industries. Coal, for example, is a sedimentary rock used as a fuel. Limestone is the raw material for the cement industry.

For Scientific Research

The fossilised remains of plants and animals present in rocks help in scientific research. Sedimentary rocks in particular preserve fossils, which scientists study to understand life on Earth millions of years ago.

Soil Erosion Prevention

Rocks are used for bunding and rock barriers that prevent soil erosion. Farmers and engineers use rocks to build boundaries around fields and riverbanks to stop soil from being washed away.

What Are the Uses of Each Type of Rock

The table below shows different types of rocks and their uses:

Rock Types	Their Uses
Igneous Rocks	Grinding stones used to prepare paste or powder of spices and grains are made of granite. Basalt, another igneous rock, forms the Deccan Plateau and is used in construction.
Sedimentary Rocks	Sandstone and limestone are widely used in construction. Limestone is the raw material for the cement industry. Chalk is used for writing on blackboards.
Metamorphic Rocks	Granite and marble are used for building homes and making countertops. Marble is one of the most prized building and sculpting materials in the world. Slate is used for roofing and flooring.

Minerals From Rocks Used in Daily Life

Rocks also give us the minerals that power our modern world. Pencil lead is made of graphite. Telephones have copper wiring. Carpets in our homes contain sulphur and chromite. Quartz is commonly used in clocks. Toothpaste is made white with titanium oxide, which comes from minerals called rutile, ilmenite, and anatase.

Key Terms to Remember

Rock: A natural mass of mineral matter that makes up the Earth's crust.
Igneous Rock: Formed from the cooling of molten magma. Examples: granite and basalt.
Sedimentary Rock: Formed from compressed sediments. Examples: sandstone, limestone, and chalk.
Metamorphic Rock: Formed from igneous or sedimentary rocks under heat and pressure. Examples: marble and slate.
Fossil: The preserved remains of ancient plants and animals, found in sedimentary rocks.
Rock Cycle: The continuous process by which rocks change from one type to another.

Quick Revision Points for Exam

Rocks are used in construction: houses, buildings, roads, bridges, and embankments.
Granite is used for grinding stones; marble (metamorphic) for monuments.
The Taj Mahal is made of marble; the Red Fort is made of red sandstone.
Rocks are used as gemstones in jewellery.
Minerals from rocks are used as fuels (coal), in medicines, fertilisers, and industries.
Chalk (sedimentary) is used for writing; stone inscriptions preserve history.
Fossils in sedimentary rocks help in scientific research.
Rock barriers prevent soil erosion.
The three types of rocks are igneous, sedimentary, and metamorphic.