Rocks and rock types - class-VI

• Marble is formed when limestone is subjected to intense heat and pressure leading to its metamorphism i.e. change in form. Hence marble is called a metamorphic rock

Igneous rocks are called as primary rocks because they originate during the formation of upper crust of the earth on cooling, solidification and crystallization of hot and liquid magmas after the origin of the earth. 

Limestone, Sandstone, and Shale are examples of sedimentary rocks but Marble is an example of metamorphic rock. 

Magma is the term for molten rock located beneath the Earth's surface. Once it reaches the surface through volcanic activity, it is referred to as lava.

• Igneous rocks are the rocks that are formed by the cooling of hot masses or by the solidification of molten matter, hence option B is correct.
• Hard rock is any rock that is hard. It is a very general term.
• Aqueous rocks are the rocks deposited by the water and they get formed in layers or strata.
• Volcanic rocks are the rocks coming out of the volcanic eruption which are mostly of igneous origin but as already the specific option of Igneous rocks is provided, option D is not the most suitable answer.

• When any rock gets broken it eventually gets eroded and transported to a different place where it settles down in layers. When many layers of such broken materials are piled up and take the form of a rock then it is called a sedimentary rock, hence option A is correct.
• Soft rock is a general term for any soft rock.
• Organic rock is a sedimentary rock which has high organic carbon.

• Marble, Slate and quartz are formed after metamorphism ie change in their original form due to extreme temperatures and pressure.
• Granite is an igneous rock, thus option B is correct.

Igneous rocks are formed during the formation of the upper crust of the earth on cooling, solidification, and crystallization of hot and liquid magmas after the origin of the earth. Igneous rocks are mostly associated with the volcanic activities and igneous rocks are generally found in the volcanic zones.

None of the above

• Permeable rocks are the rocks having interconnected pores which allow the water to seep through them. Hence option A is correct.
• Sedimentary rocks and metamorphic rocks are a  broad classification of rocks.
• Mushroom rocks derive their name out of their shape.

• When the lava solidifies before reaching the surface, it gives rise to the rocks called plutonic rocks.
• Volcanic rocks are formed when lava solidifies on the surface of the earth.
• Sedimentary and metamorphic rocks are not directly related to lava.
• Hence option B is the correct answer.

Stalactites and stalagmites are the depositional landforms of limestone areas. The calcareous deposits from dripping of water in dry caves are called dripstones. The columns of dripstones hanging from the cave ceiling are called stalactites while the calcareous columns of dripstones growing upward from the cave floor are known as stalagmites.

Igneous rocks begin the rock cycle, and are therefore called primary rocks. Two major divisions include- volcanic or extrusive rocks that form when magma is ejected from the Earth's crust, and intrusive rocks, which are created below the surface.

Marble is a metamorphic rock formed from the metamorphism of limestone or dolomite. The heat and pressure cause the calcite in the limestone to recrystallize.

Precious stones like rubies, emeralds, and sapphires are typically found in metamorphic rocks, which form under high pressure and temperature conditions that allow for the growth of these crystals.

• Granite rock is formed from the cooling of lava so it is found as an igneous rock. Hence option A is correct.
  
• Rest options are of different category of rocks.

Quartzite is a metamorphic rock that is formed by interlocking quartz grains from quartz sandstone. The rock is hard rock, nonfoliated.

The process of transformation of existing rocks is known to be metamorphism.

Marble is formed from the sedimentary rocks. It is also used in making statues.

Sandstone is a sedimentary rock composed primarily of sand-sized mineral particles or rock fragments, most commonly quartz, because quartz is highly resistant to weathering.

Metamorphic rocks are formed by the transformation of igneous or sedimentary rocks into different kinds of rocks under intense heat and pressure.
Marble is formed by metamorphosis of limestone.
Gneiss is formed by metamorphosis of granite.
Slate is dark grey shiny rock made by metamorphism of shale. Used to make slates and blackboards.

Pumice is a light volcanic rock. It has a lot of pores in it. It is an igneous rock. The rock is light enough to float on water until it becomes waterlogged. Pumice is a very light rock which is used as body scrubber and to polish floor.

The word 'igneous' is derived from a Latin word 'ignis' meaning fire. Igneous rocks are known as primary rocks as they are formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet's mantle or crust.

• Rocks are basically classified as igneous, metamorphic and sedimentary rocks.
• Organic rocks are a type of sedimentary rock which contain high amounts of organic carbon.
• Hence option D is correct.

Igneous rocks are rocks formed by the solidification (due to the cooling) of volcanic eruptions (lava) and magma.

Contact metamorphism is a type of metamorphism where the texture of rock minerals are changed by means of heat, due to contact with magma, which is generally an igneous intrusion, i.e; the formed magma is trapped beneath the Earth's surface.

Metamorphic rocks are formed by the transformation of existing rocks under intense heat and pressure. This process typically makes them more compact and harder than their original parent rocks, not softer.

Argillaceous rocks are those that are primarily composed of clay minerals. Shale is a classic example of an argillaceous sedimentary rock.