Three rock types and the rock cycle: classify the process

Formation gives the categories

NCERT describes igneous rocks forming when molten material cools and solidifies. Sedimentary rocks form from deposited particles, while heat and pressure can transform existing rocks into metamorphic rocks.

The textbook gives limestone changing into marble as an example of metamorphism. These categories describe formation, rather than simply a rock’s colour or its use in a building.

A cycle is not one fixed queue

Rock material can undergo different processes over time. Melting and cooling, breakdown and deposition, or heat and pressure offer different routes. A rock-cycle diagram is therefore a map of transformations rather than a claim that every specimen follows one identical timetable.

A polished surface is not enough to establish a rock’s geological origin. Appearance can be a clue, but a classification question asks about the formation process.

An original sorting exercise

Write three hypothetical descriptions: cooled molten material, compacted deposited fragments and existing rock changed by heat and pressure. Match each description to its rock category before adding a named example. This tests the definition instead of recognition of one familiar specimen.

Next draw arrows labelled with processes rather than writing only category names. Ask whether your arrow requires melting or whether a solid rock is being transformed. Explaining that distinction improves a short answer much more than adding an unsupported age estimate.

This is static geography and geology. It does not identify a particular stone from a photograph or claim that all rocks of one type have the same colour, age or strength. Use the linked textbook for the basic formation framework and sample-specific geological evidence for an actual identification.

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