2022Minerals and Rocks - First Day Cover

The science that explores the formation and classification of rocks is called petrology An important point to note is that rocks make up the lithosphere – a solid mass of rocks with a thickness of 5 to 70 kilometers, which encompasses the Earth's crust (the solid surface layer of the planet Earth) and the Earth's upper mantle (the thickest layer containing the majority of our planet's material). Just beneath the solid lithosphere lies the central part of the Earth's mantle – the asthenosphere – a layer of molten rock called magma. The lower part of the Earth's mantle maintains a solid state as a result of high pressure and reaches a depth of 2,900 kilometers. Beneath the mantle all the way to the center lies the Earth's core, which is made up mostly of iron.