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प्रश्न
What is meant by a rock?
उत्तर
A rock can be defined as “an aggregate of minerals that forms a more or less definite unit of the earth’s crust”. A rock does not possess a definite composition like that of a chemical compounds, but is usually a mixture of various minerals.
The bulk of rocks is made up of silica or quartz and feldspar. Feldspar are composed of silica, aluminium, potassium and sodium or calcium. Some rocks are composed of grains cemented together, while several other are crystalline, compact or even glass-like.
All material (whether hard like stone or sand) of which the crust of the earth is composed are called rocks e.g, stone, clay, lava, sand, chalk, salt, coal marble etc.
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संबंधित प्रश्न
The photograph shows you a type of rock that is widely used in the construction industry.
- Name the type of rock.
- How is it formed?
State two points of distinction between rocks and minerals.
Explain this term associated with rocks: Metamorphism
Name the main types of rocks.
How are chemically-formed sedimentary rocks produced?
Classify the following rock: Marble
Give one word for the following.
The outer layer of the earth.
What is the basis for the classification of rocks?
How is Plutonic rock formed?
Distinguish between Intrusive and Extrusive Rocks
Fossils are found in.
Match the following:
| A. | Basalt | 1. | Anthracite |
| B. | Limestone | 2. | Extrusive igneous |
| C. | Coal | 3. | Metamorphic rock |
| D. | Gneiss | 4. | Sedimentary rock |
What are metamorphic rocks?
This is the storehouse of rocks.
An aggregate of minerals on the Earth’s Crust is called ______.
Statement (1): Sedimentary rocks consist of many layers.
Statement (2): Sedimentary rocks are formed by the sediments deposited at different points of time.
Statement (1): Sedimentary rocks consist of many layers.
Statement (2): Sedimentary rocks are formed by the sediments deposited at different points of time.
Match the following.
| A. | Basalt | 1. | Anthracite |
| B. | Limestone | 2. | Extrusive igneous |
| C. | Coal | 3. | Metamorphic rock |
| D. | Gneiss | 4. | Sedimentary rock |
Statement (1): Sedimentary rocks consist of many layers.
Statement (2): Sedimentary rocks are formed by the sediments deposited at different points of time.
