What are rocks:
Rocks are naturally occurring solid masses or aggregates of minerals or mineraloid matter. They form the solid outer layer of the Earth, known as the lithosphere, and can vary greatly in size, composition, and texture.
Types of Rocks
Rocks are classified into three main types based on how they are formed:
1. Igneous Rocks – “Born from Fire”
These are formed from the cooling and solidification of magma or lava.
Types of Igneous Rocks:
Intrusive (Plutonic): Formed inside the Earth from slowly cooled magma. Large crystals.
Example: Granite, Diorite
Extrusive (Volcanic): Formed on the surface from rapidly cooled lava. Small or no crystals.
Example: Basalt, Pumice, Obsidian
2. Sedimentary Rocks – “Layered Over Time”
These are formed by the accumulation and compaction of sediments like sand, silt, clay, and organic material.
Types of Sedimentary Rocks:
Clastic: Made from fragments of other rocks.
Example: Sandstone, Shale, Conglomerate
Chemical: Formed from mineral-rich water evaporating or precipitating.
Example: Limestone, Halite
Organic: Made from the remains of plants and animals.
Example: Coal, Chalk
3. Metamorphic Rocks – “Changed by Heat and Pressure”
These form when existing rocks are transformed by heat, pressure, or chemical processes—without melting.
Types of Metamorphic Rocks:
Foliated: Have layered or banded appearance due to pressure.
Example: Slate, Schist, Gneiss
Non-foliated: No visible layers.
Example: Marble (from limestone), Quartzite (from sandstone)
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