Limestone, when subjected to heat and pressure, transforms into marble.

Here's a breakdown:

* Limestone: A sedimentary rock primarily composed of calcium carbonate (CaCO3).

* Heat and Pressure: These conditions cause the calcite crystals in limestone to recrystallize and become interlocked.

* Marble: A metamorphic rock with a distinctive, often swirling pattern due to the recrystallized calcite.

Marble is widely used for sculptures, building materials, and decorative purposes due to its beauty and durability.