Which type of rock is formed from cooling and solidification of lava ?
Igneous
Rock formed by the cooling and solidification of molten material is igneous rock — option 1.
The name says it. “Igneous” comes from the Latin ignis, fire. These are the primary rocks of the Earth’s crust: every sedimentary and metamorphic rock is ultimately derived from them, which is why they are also called parent rocks.
| Type | How it forms | Examples |
|---|---|---|
| Igneous | Cooling and solidification of magma or lava | Basalt, granite, gabbro, pumice |
| Sedimentary | Compaction and cementation of transported sediment, or chemical or organic deposition | Sandstone, shale, limestone, coal |
| Metamorphic | Existing rock altered in the solid state by heat and pressure | Marble from limestone, slate from shale, gneiss from granite |
Magma against lava — a distinction the question relies on. Molten rock below the surface is magma; once it reaches the surface it is lava. Magma cooling slowly at depth gives intrusive or plutonic rock such as granite, and the slow cooling allows large, visible crystals to grow. Lava cooling quickly in the open air gives extrusive or volcanic rock such as basalt, with crystals too small to see, and sometimes glassy obsidian or frothy pumice where cooling is fastest. Since the question specifies lava, the product is extrusive igneous rock.
An Indian example. The Deccan Traps of Maharashtra, Madhya Pradesh and Gujarat are vast sheets of basalt poured out by fissure eruptions about 66 million years ago. They weather into the black regur or cotton soil that supports the region’s cotton crop.
Why “crystal” is not an option. A crystal is a solid whose atoms are arranged in a regular repeating lattice. Crystals occur in all three rock families, so it names a structure, not a class of rock.
Hence, the answer is Igneous.
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