Rocks and Minerals Class 2

Table of Content

  • Rocks
  • Hard Rocks
  • Soft Rocks
  • Difference between Hard rock and Soft rock
  • Rock Cycle
  • Types of Rocks
  • Minerals
  • FAQs
  • Rocks

    Rocks are a big part of our Earth. They make up almost everything around us, like hills, mountains, and valleys. We can find rocks under the ground, in the seas, and in rivers.

    Rocks come in many different colours and types. Some rocks are shiny, some are hard, and some are soft. They have different uses depending on their hardness and type.

    Examples of rocks are granite, marble, sandstone etc.

    Hard Rocks

    1. Hard rocks include granite, sandstone, and marble.
    2. Marble is used to make beautiful floors, statues, and furniture.
    3. Granite is super strong and is great for making statues and floors. Some kitchens even have countertops made of granite.
    4. Sandstone is another hard rock that is used for building things like temples and forts.
    5. Examples of hard rocks are granite, basalt, marble, gneiss etc.

    Different types of hard rocks

    Soft Rocks

    1. Coal and slate are examples of soft rocks.
    2. Slate is a soft, grey-coloured rock. Some houses have roofs made of slate. We also use slate for blackboards and writing slates.
    3. Coal is a soft rock that we use as fuel in steam engines, factories, and for cooking.
    4. Examples of soft rocks are sandstone, shale, limestone, siltstone, chalk, mudstone etc.

    Different types of soft rocks

    Difference Between Hard Rock and Soft Rock

    Feature

    Hard Rock

    Soft Rock

    Definition

    Dense, durable rock with high hardness

    Less dense, more easily weathered rock

    Examples

    Granite, basalt, quartzite

    Limestone, sandstone, shale

    Texture

    Rough, coarse

    Smooth, fine

    Formation

    Formed from cooling magma or high-pressure conditions

    Formed from sedimentation and compression

    Uses

    Construction, monuments, road building

    Building materials, ornamental stone

    Weathering

    Resists weathering and erosion

    Weathers and erodes more quickly

    Density

    High density and hardness

    Lower density and hardness

    Color

    Often dark or varied in color

    Typically lighter in color

    Strength

    Generally stronger and more durable

    Generally weaker and less durable

    Rock Cycle

    The rock cycle is like a never-ending process, where they go through changes and transformations to become new rocks.

    The Rock cycle

    Types of Rocks

    There are three types of rocks:

    1. Igneous Rocks

    a) These rocks are formed when hot, molten materials called magma or lava cool down and become solid.
    b) Igneous rocks are born from the cooling of magma or lava from the earth’s core.

    Examples: Granite, scoria, obsidian, and pumice.

    Different types of Igneous rocks

    2. Sedimentary Rocks

    a) Sedimentary rocks are formed when small pieces of rocks, called sediments, get buried and pressed together over a long time.
    b) Sedimentary rocks are made from these compressed and cemented sediments.

    Examples: Sandstone, limestone, shale, gypsum, and conglomerate.

    Different types of Sedimentary rocks

    3. Metamorphic Rocks

    a) Metamorphic rocks are formed when existing rocks are put under a lot of heat and pressure deep inside the Earth for a very long time.

    Examples: marble, slate, quartzite, and gneiss.

    Different types of Metamorphic rocks

    Minerals

    Minerals are like tiny ingredients that make up rocks. They come in different shapes, sizes, and colours.
    These minerals have different purposes and are used to make many things we use in our daily lives.

    Some of the examples of minerals are:

    Talc: This is a very soft mineral that is used to make talcum powder.

    Silica: Silica is a mineral that can be found in sand. It is used to make glass, like the glass in windows or bottles.

    China clay: China clay is also a soft mineral. It is used to make pottery, like beautiful plates and cups that we use for eating and drinking.

    Diamond: Diamonds are the hardest minerals found in nature. They are used to make beautiful jewellery and cut glass.

    Graphite: Graphite is a soft mineral that is used to make pencil lead.

    Quartz: Quartz is a mineral that is used to make watch dials.

    Different types of minerals

    Frequently Asked Questions

    1. What are some examples of soft rocks?

    Examples of soft rocks include limestone, sandstone, shale, and mudstone. These rocks are easier to cut and shape.

    2. What is the difference between rocks and minerals?

    Rocks are made of different minerals mixed together, while minerals are single, natural substances with their own shapes and colours. Rocks are like a mix, minerals are like individual parts.

    3. What are some examples of hard rocks?

    Examples of hard rocks include granite, basalt, and quartzite. They are tough and durable, often used in construction.

    4. Give some examples of minerals;

    Here are some example of minerals:

    a. Mica
    b. Gypsum
    c. Pyrite etc.

    5. How are rocks formed?

    Rocks can be formed in different ways, like cooling lava, pressing sediments together, or changing from other rocks.

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