Previous Year Question

Quartzite is a metamorphic rock formed through the metamorphism of quartz-rich sandstone.

When sandstone is subjected to intense heat and pressure, its quartz grains recrystallize and become strongly interlocked.

This process produces quartzite—a hard, compact and generally non-foliated metamorphic rock.

Among the other options, limestone metamorphoses into marble; shale may progressively transform into slate, phyllite or schist, whereas obsidian is volcanic glass.