Rocks and Earth Materials

Quartzite is a metamorphic rock formed from sandstone when the quartz grains recrystallize under heat and pressure, creating a hard, interlocking crystal structure. The transformation eliminates the original sedimentary texture while maintaining the chemical composition.

Two names for a magnetic rock are load stone and magnetite.

Quartzite is the metamorphic rock formed from sandstone. Under intense heat and pressure, the quartz grains in sandstone recrystallize to form quartzite, a much harder and more compact rock. Marble is the metamorphic form of limestone, gneiss can form from various rocks depending on composition, and granite is an igneous rock, not metamorphic.

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Marble is a metamorphic rock formed from limestone under heat and pressure. Both marble and limestone are primarily composed of calcium carbonate (CaCO3). The metamorphic process recrystallizes the calcite in limestone, giving marble its characteristic crystalline structure. Graphite and coal are carbon-based, while basalt is an igneous rock.

Edward Suess classified Earth's interior into three compositional layers: Sial (silica + aluminum, the upper continental crust), Sima (silica + magnesium, the oceanic crust and lower continental crust), and Nife (nickel + iron, the core). Mohorovicic discovered the Moho discontinuity, Gutenberg discovered the core-mantle boundary, and Connard identified the Conrad discontinuity within the crust.

Silicon (28%) and oxygen (46%) are the two most abundant elements in Earth's crust by mass, combined primarily as silicates and silica. Together they account for about 75% of the crust's composition. Nitrogen is mainly in the atmosphere, while carbon is present but not in crustal abundance.

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When limestone is subjected to heat and pressure (metamorphism), it recrystallizes to form marble. Graphite comes from carbon, quartz is a silica mineral, and granite is igneous - none form from limestone metamorphism.

Petroleum is a fossil fuel found in sedimentary rocks, which are formed by the accumulation and cementation of mineral and organic particles. Most petroleum deposits are found in sedimentary basins where ancient marine organisms were buried and transformed over millions of years.

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Shield volcanoes are mostly made up of basalt, a type of lava that is very fluid when it erupts. The upcoming lava moves in the form of a fountain and throws out the cone at the top of the vent, and develops into cinder cone.

When the lava makes its way through cracks and the fissures developed in the land, it solidifies almost perpendicular to the ground. It gets cooled in the same position to develop a wall-like structure. Such structures are called dykes. These are the most commonly found intrusive forms in the western Maharashtra area.

These volcanoes outpour highly fluid lava that flows for long distances. Some parts of the world are covered by thousands of sq. km of thick basalt lava flows. There can be a series of flows with some flows attaining thickness of more than 50 m. Individual flows may extend for hundreds of km. The Deccan Traps from India, presently covering most of the Maharashtra plateau, are a much larger flood basalt province.