Rocks :

• Rocks are a mixture of different minerals formed by natural processes in the lithosphere.
• The earth’s crust is made of rocks and soil.
• Silica, aluminium, magnesium and iron are the major rock forming minerals. There are other minerals, too, in different rocks.
• Properties of rocks depend on the constituent minerals and their proportion as well as on the formation process.

Types of rocks :

There are the following three types of rocks according to their formation process :

• Igneous rocks/ Primary rocks
• Sedimentary rocks
• Metamorphic rocks.

(i) Igneous rocks :

• When molten material cools, known as magma within the crust and lava on the surface, it solidifies, giving rise to igneous rocks.
• These are also referred to as primary rocks. We do not get fossils in these rocks.
• Basalt is a major example of igneous rock.

(ii) Sedimentary rocks :

• The rocks disintegrate/decompose as a result of heat, rivers, glaciers, wind, and so on. These rock particles are transported to low-lying places and deposited there. Layers of sediment are deposited one after the other in this manner.
• The top layers exert significant pressure on the lower layers, resulting in material compaction and the formation of sedimentary rocks.
• These rocks may include fossils. These rocks are typically fragile and light.
• Sedimentary rocks include sandstone, limestone, shale, corals, and others.

Metamorphic rocks :

• Igneous or sedimentary rocks are subjected to huge pressure and heat as a result of volcanic activity and other earth movements. As a result, the crystals in the original rocks re-crystallize/metamorphose, resulting in the production of metamorphic rocks, corals, and other sedimentary rocks.
• These rocks do not contain fossils. These rocks are heavy and hard.
• Gneiss, Marble, Diamond, Slate, etc. are metamorphic rocks.

Fossils :

• The impressions of buried remains of dead animals or plants become putrefied in the rocks as a result of high pressure. These are known as fossils.
• The study of fossils provides information about the life in that period.

Maharashtra's major rock distribution :

• Basalt rock formed out of volcanic eruption has spread over a vast region of
• Granite rock is found mainly in the eastern parts and in South Konkan.
• Laterite is found in South Konkan in the districts of Sindhudurg and Ratnagiri.
• Sedimentary rock is found in Nandurbar, Dhule, Jalgaon, Buldhana, Akola and Amravati districts of Maharashtra.

Mineral wealth of Maharashtra :

• Because of the thick and extensive layers of Basalt, Maharashtra does not have large reserves of mineral wealth
• In Maharashtra, mining activity is concentrated in South Konkan and in Eastern Maharashtra.